MyBatis学习总结 + 【手写MyBatis底层机制焦点】

MyBatis条记

MyBatis介绍

MyBatis 是一个长期层框架

• 前身是ibatis, 在ibatis3.x 时，更名为MyBatis
  
• MyBatis 在java 和sql 之间提供更机动的映射方案
  
• mybatis 可以将对数据表的操纵(sql,方法)等等直接剥离，写到xml 配置文件，实现和java
  代码的解耦
  
• mybatis 通过SQL 操纵DB, 建库建表的工作必要程序员完成
  

相关文档

MyBatis 中文手册、
https://mybatis.org/mybatis-3/zh/index.html
https://mybatis.net.cn/
为什么必要MyBatis？

• 传统jdbc连接数据库必要本身编写，不同一标准
  
• 程序不是OOP的方式编写的
  
• SQL语句是写在程序中，属于硬编码，没有解耦
  
• mybatis 可以将对数据表的操纵(sql,方法)等等直接剥离，写到xml 配置文件，实现和java
  代码的解耦
  
• MyBatis 是一个长期层框架所以它同一
  
• MyBatis 是OOP方式操纵数据库
  

MyBatis案例

实体类

1. @Setter
2. @Getter
3. @AllArgsConstructor
4. @NoArgsConstructor
5. @ToString
6. public class Monk {
7. <mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>private Integer id;
10. <mappers>
11.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
12. </mappers>private String nickname;
13. <mappers>
14.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
15. </mappers>private String skill;
16. <mappers>
17.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
18. </mappers>private String grade;
19. <mappers>
20.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
21. </mappers>private Double salary;
22. <mappers>
23.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
24. </mappers>private String birthTime;
25. <mappers>
26.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
27. </mappers>private Date entry;
28. }

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mapper接口

• 只是一个接口
  
• 该接口用于声明操纵monster表的方法
  
• 这些方法可以通过注解或者xml文件实现
  

1. public interface MonkMapper {
3. <mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>void addMonk(Monk monk);
6. }

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mapper.xml

• 这是一个mapper xml 文件
  
• 该文件可以去实现对应的接口的方法
  
• namespace 指定该xml文件和哪个接口对应
  

1. <?xml version="1.0" encoding="UTF-8" ?>
2. <!DOCTYPE mapper
3.   
4. <mappers>
5.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
6. </mappers><properties resource="jdbc.properties"/>  PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
7.   
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers><properties resource="jdbc.properties"/>  "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
11. <mapper namespace="com.code_study.mapper.MonkMapper">
13. <mappers>
14.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
15. </mappers>
16. <mappers>
17.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
18. </mappers>
19. <mappers>
20.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
21. </mappers><insert id="addMonk" parameterType="Monk">
22.   
23. <mappers>
24.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
25. </mappers><properties resource="jdbc.properties"/>  INSERT INTO `monk`
26.   
27. <mappers>
28.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
29. </mappers><properties resource="jdbc.properties"/>  
30. <mappers>
31.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
32. </mappers><properties resource="jdbc.properties"/>(`nickname`,`skill`,`grade`,`salary`,`birthTime`,`entry`)
33.   
34. <mappers>
35.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
36. </mappers><properties resource="jdbc.properties"/>  VALUES(#{nickname},#{skill},#{grade},#{salary},#{birthTime},#{entry})
37. <mappers>
38.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
39. </mappers></insert>
41. </mapper>

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原生的API和注解的方式

Mybatis原生的API调用

添加

1. @Test
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers>public void myBatisNativeCrud(){
5.   
6. <mappers>
7.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
8. </mappers><properties resource="jdbc.properties"/>  Monk monk = new Monk();
10.   
11. <mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers><properties resource="jdbc.properties"/>  monk.setBirthTime("1999-9-9 10:11:02");
14.   
15. <mappers>
16.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
17. </mappers><properties resource="jdbc.properties"/>  Calendar instance = Calendar.getInstance();
19.   
20. <mappers>
21.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
22. </mappers><properties resource="jdbc.properties"/>  instance.set(Calendar.YEAR,2020);
23.   
24. <mappers>
25.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
26. </mappers><properties resource="jdbc.properties"/>  instance.set(Calendar.MONTH,Calendar.OCTOBER);
27.   
28. <mappers>
29.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
30. </mappers><properties resource="jdbc.properties"/>  instance.set(Calendar.DAY_OF_MONTH,15);
31.   
32. <mappers>
33.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
34. </mappers><properties resource="jdbc.properties"/>  Date time = instance.getTime();
35.   
36. <mappers>
37.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
38. </mappers><properties resource="jdbc.properties"/>  monk.setEntry(time);
39.   
40. <mappers>
41.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
42. </mappers><properties resource="jdbc.properties"/>  monk.setGrade("大宗师");
43.   
44. <mappers>
45.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
46. </mappers><properties resource="jdbc.properties"/>  monk.setNickname("法海");
47.   
48. <mappers>
49.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
50. </mappers><properties resource="jdbc.properties"/>  monk.setSalary(200.5);
51.   
52. <mappers>
53.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
54. </mappers><properties resource="jdbc.properties"/>  monk.setSkill("大威天龙");
56.   
57. <mappers>
58.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
59. </mappers><properties resource="jdbc.properties"/>  int insert = sqlSession.insert("com.code_study.mapper.MonkMapper.addMonk", monk);
60.   
61. <mappers>
62.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
63. </mappers><properties resource="jdbc.properties"/>  System.out.println("insert~~" + insert);
64.   
65. <mappers>
66.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
67. </mappers><properties resource="jdbc.properties"/>  System.out.println("操作成功");
68.    }

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删除

1.   <mappers>
2. <mappers>
3. <mappers>
4.         <package name="com.cody_study.mapper"/>
5. </mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
6. </mappers><mapper />
7. </mappers>@Test
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers>public void myBatisNativeCrud(){
11. <mappers>
12. <mappers>
13. <mappers>
14.         <package name="com.cody_study.mapper"/>
15. </mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
16. </mappers><mapper />
17. </mappers><mappers>
18. <mappers>
19. <mappers>
20.         <package name="com.cody_study.mapper"/>
21. </mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
22. </mappers><mapper />
23. </mappers>int delete = sqlSession.delete("com.code_study.mapper.MonkMapper.deleteMonk", 6);
24.   
25. <mappers>
26.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
27. </mappers><properties resource="jdbc.properties"/>  System.out.println("delete~~" + delete);
28.   
29. <mappers>
30.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
31. </mappers><properties resource="jdbc.properties"/>  System.out.println("操作成功");
32.   
33. <mappers>
34.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
35. </mappers><properties resource="jdbc.properties"/>}

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修改

1. @Test
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers>public void myBatisNativeCrud(){
5. <mappers>
6. <mappers>
7. <mappers>
8.         <package name="com.cody_study.mapper"/>
9. </mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
10. </mappers><mapper />
11. </mappers><mappers>
12. <mappers>
13. <mappers>
14.         <package name="com.cody_study.mapper"/>
15. </mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
16. </mappers><mapper />
17. </mappers> Monk monk = new Monk();
19.   
20. <mappers>
21.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
22. </mappers><properties resource="jdbc.properties"/>  monk.setBirthTime("1999-9-9 10:11:02");
23.   
24. <mappers>
25.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
26. </mappers><properties resource="jdbc.properties"/>  Calendar instance = Calendar.getInstance();
28.   
29. <mappers>
30.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
31. </mappers><properties resource="jdbc.properties"/>  instance.set(Calendar.YEAR,2020);
32.   
33. <mappers>
34.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
35. </mappers><properties resource="jdbc.properties"/>  instance.set(Calendar.MONTH,Calendar.OCTOBER);
36.   
37. <mappers>
38.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
39. </mappers><properties resource="jdbc.properties"/>  instance.set(Calendar.DAY_OF_MONTH,15);
40.   
41. <mappers>
42.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
43. </mappers><properties resource="jdbc.properties"/>  Date time = instance.getTime();
44.   
45. <mappers>
46.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
47. </mappers><properties resource="jdbc.properties"/>  monk.setEntry(time);
48.   
49. <mappers>
50.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
51. </mappers><properties resource="jdbc.properties"/>  monk.setGrade("大宗师");
52.   
53. <mappers>
54.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
55. </mappers><properties resource="jdbc.properties"/>  monk.setNickname("法海");
56.   
57. <mappers>
58.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
59. </mappers><properties resource="jdbc.properties"/>  monk.setSalary(200.5);
60.   
61. <mappers>
62.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
63. </mappers><properties resource="jdbc.properties"/>  monk.setSkill("乾坤大挪移");
64.   
65. <mappers>
66.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
67. </mappers><properties resource="jdbc.properties"/>  monk.setId(8);
68.   
69. <mappers>
70.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
71. </mappers><properties resource="jdbc.properties"/>  int update = sqlSession.update("com.code_study.mapper.MonkMapper.updateMonk", monk);
72.   
73. <mappers>
74.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
75. </mappers><properties resource="jdbc.properties"/>  System.out.println("update~~" + update);
76.   
77. <mappers>
78.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
79. </mappers><properties resource="jdbc.properties"/>  System.out.println("操作成功");
80.   
81. <mappers>
82.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
83. </mappers><properties resource="jdbc.properties"/>}

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查询

1. @Test
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers>public void myBatisNativeCrud(){
5. <mappers>
6. <mappers>
7. <mappers>
8.         <package name="com.cody_study.mapper"/>
9. </mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
10. </mappers><mapper />
11. </mappers><mappers>
12. <mappers>
13. <mappers>
14.         <package name="com.cody_study.mapper"/>
15. </mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
16. </mappers><mapper />
17. </mappers>List<Monk> monks =
18.   
19. <mappers>
20.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
21. </mappers><properties resource="jdbc.properties"/>  
22. <mappers>
23.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
24. </mappers><properties resource="jdbc.properties"/>sqlSession.selectList("com.code_study.mapper.MonkMapper.findAllMonk");
25.   
26. <mappers>
27.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
28. </mappers><properties resource="jdbc.properties"/>  for (Monk monk : monks) {
29.   
30. <mappers>
31.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
32. </mappers><properties resource="jdbc.properties"/>  
33. <mappers>
34.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
35. </mappers><properties resource="jdbc.properties"/>System.out.println("monk= "+ monk);
36.   
37. <mappers>
38.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
39. </mappers><properties resource="jdbc.properties"/>  }
41.   
42. <mappers>
43.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
44. </mappers><properties resource="jdbc.properties"/>  if (sqlSession != null){
45.   
46. <mappers>
47.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
48. </mappers><properties resource="jdbc.properties"/>  
49. <mappers>
50.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
51. </mappers><properties resource="jdbc.properties"/>sqlSession.commit();
52.   
53. <mappers>
54.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
55. </mappers><properties resource="jdbc.properties"/>  
56. <mappers>
57.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
58. </mappers><properties resource="jdbc.properties"/>sqlSession.close();
60.   
61. <mappers>
62.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
63. </mappers><properties resource="jdbc.properties"/>  }
64. <mappers>
65.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
66. </mappers>}

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Mybatis注解的方式操纵

添加

1.   /*
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers>useGeneratedKeys = true : 表示可以返回自增长的值
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers>keyProperty = "id"  
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers><properties resource="jdbc.properties"/>: 表示 自增值对应对象的哪个属性
11. <mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers>keyColumn = "id"  
14. <mappers>
15.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
16. </mappers><properties resource="jdbc.properties"/>  : 表示 自增值对应表的哪个字段
17. <mappers>
18.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
19. </mappers>如果 keyProperty = "id" 和  keyColumn = "id"  一致，可以只保留 keyProperty = "id"
20. <mappers>
21.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
22. </mappers> */
23. <mappers>
24.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
25. </mappers>@Insert(value = "INSERT INTO `monk` " +
26.   
27. <mappers>
28.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
29. </mappers><properties resource="jdbc.properties"/>  
30. <mappers>
31.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
32. </mappers><properties resource="jdbc.properties"/>"  
33. <mappers>
34.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
35. </mappers><properties resource="jdbc.properties"/>  
36. <mappers>
37.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
38. </mappers><properties resource="jdbc.properties"/>(`nickname`,`skill`,`grade`,`salary`,`birthTime`,`entry`) " +
39.   
40. <mappers>
41.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
42. </mappers><properties resource="jdbc.properties"/>  
43. <mappers>
44.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
45. </mappers><properties resource="jdbc.properties"/>"  
46. <mappers>
47.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
48. </mappers><properties resource="jdbc.properties"/>  VALUES(#{nickname},#{skill},#{grade},#{salary},#{birthTime},#{entry})")
49. <mappers>
50.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
51. </mappers>@Options(useGeneratedKeys = true,keyProperty = "id",keyColumn = "id")
52. <mappers>
53.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
54. </mappers>void addMonk(Monk monk);

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删除

1.   @Delete(value = "  DELETE FROM `monk` WHERE id = #{id}")
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers>void deleteMonk(Integer id);

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修改

1. @Update(value = " UPDATE `monk` " +
2.   
3. <mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers><properties resource="jdbc.properties"/>  
6. <mappers>
7.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
8. </mappers><properties resource="jdbc.properties"/>"  
9. <mappers>
10.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
11. </mappers><properties resource="jdbc.properties"/>  SET `nickname`=#{nickname}, " +
12.   
13. <mappers>
14.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
15. </mappers><properties resource="jdbc.properties"/>  
16. <mappers>
17.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
18. </mappers><properties resource="jdbc.properties"/>"  
19. <mappers>
20.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
21. </mappers><properties resource="jdbc.properties"/>  
22. <mappers>
23.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
24. </mappers><properties resource="jdbc.properties"/>`skill`=#{skill}, " +
25.   
26. <mappers>
27.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
28. </mappers><properties resource="jdbc.properties"/>  
29. <mappers>
30.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
31. </mappers><properties resource="jdbc.properties"/>"  
32. <mappers>
33.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
34. </mappers><properties resource="jdbc.properties"/>  
35. <mappers>
36.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
37. </mappers><properties resource="jdbc.properties"/>`grade`=#{grade}, " +
38.   
39. <mappers>
40.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
41. </mappers><properties resource="jdbc.properties"/>  
42. <mappers>
43.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
44. </mappers><properties resource="jdbc.properties"/>"  
45. <mappers>
46.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
47. </mappers><properties resource="jdbc.properties"/>  
48. <mappers>
49.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
50. </mappers><properties resource="jdbc.properties"/>`salary`=#{salary}, " +
51.   
52. <mappers>
53.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
54. </mappers><properties resource="jdbc.properties"/>  
55. <mappers>
56.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
57. </mappers><properties resource="jdbc.properties"/>"  
58. <mappers>
59.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
60. </mappers><properties resource="jdbc.properties"/>  
61. <mappers>
62.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
63. </mappers><properties resource="jdbc.properties"/>`birthTime`=#{birthTime}, " +
64.   
65. <mappers>
66.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
67. </mappers><properties resource="jdbc.properties"/>  
68. <mappers>
69.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
70. </mappers><properties resource="jdbc.properties"/>"  
71. <mappers>
72.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
73. </mappers><properties resource="jdbc.properties"/>  
74. <mappers>
75.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
76. </mappers><properties resource="jdbc.properties"/>`entry`=#{entry} " +
77.   
78. <mappers>
79.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
80. </mappers><properties resource="jdbc.properties"/>  
81. <mappers>
82.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
83. </mappers><properties resource="jdbc.properties"/>"  
84. <mappers>
85.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
86. </mappers><properties resource="jdbc.properties"/>   WHERE id = #{id}")
87. <mappers>
88.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
89. </mappers>void updateMonk(Monk monk);

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查询单个

1. //查询-根据id
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers>@Select(value = "  select * from `monk` where id = #{id}")
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers>Monk getMonkById(Integer id);

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查询多个

1. //查询所有的Monster
2. @Select(value = "<mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers>select * from `monk`")
5. List<Monk> findAllMonk();

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mybatis-config.xml配置文件详解

根本介绍

• mybatis 的焦点配置文件(mybatis-config.xml)，好比配置jdbc 连接信息，注册mapper
  等等
  

properties 属性

• 通过该属性，可以指定一个外部的jdbc.properties 文件，引入我们的jdbc 连接信息
  

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>

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settings 全局参数界说

• 是MyBatis 中极为重要的调整设置，它们会改变 MyBatis 的运行时行为。
  

typeAliases 别名处理器

• 别名是为Java 类型命名一个短名字。它只和XML 配置有关，用来减少类名重复的部分
  
• 如果指定了别名,我们的MappperXxxx.xml 文件就可以做相应的简化处理
  
• 注意指定别名后，照旧可以利用全名的
  
• 可以直接指向包，这样包下的所有类都是取类名作为别名
  

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>   

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typeHandlers 类型处理器

• MyBatis 在设置预处理语句（PreparedStatement）中的参数或从结果集中取出一个值时，都会用类型处理器将获取到的值以合适的方式转换成 Java 类型。
  
• 用于java 类型和jdbc 类型映射
  
• Mybatis 的映射根本已经满足，不太必要重新界说
  
• 这个我们利用默认即可，也就是mybatis 会主动的将java 和jdbc 类型进行转换.
  

environments 环境

resource 注册Mapper 文件:

1. <mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>

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class:接口注解实现

1. <mappers>
2. <mappers>
3. <mappers>
4.         <package name="com.cody_study.mapper"/>
5. </mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
6. </mappers><mapper />
7. </mappers>

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url:外部路径,利用很少，不推荐

1. <mappers>
2. <mappers>
3. <mappers>
4.         <package name="com.cody_study.mapper"/>
5. </mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
6. </mappers><mapper />
7. </mappers>

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package 方式注册

1. <mappers>
2. <mappers>
3. <mappers>
4.         <package name="com.cody_study.mapper"/>
5. </mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
6. </mappers><mapper />
7. </mappers>

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XxxMapper.xml<mappers>
<mappers>
<mappers>
        <package name="com.cody_study.mapper"/>
</mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
</mappers><mapper />
</mappers>SQL映射文件

根本介绍

​<mappers>
<mappers>
<mappers>
        <package name="com.cody_study.mapper"/>
</mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
</mappers><mapper />
</mappers>MyBatis 的真正强大在于它的语句映射(在XxxMapper.xml 配置), 由于它的异常强大, 如
果拿它跟具有雷同功能的JDBC 代码进行对比，你会立即发现省掉了将近95% 的代码。
MyBatis 致力于减少利用成本，让用户能更专注于SQL 代码。
SQL 映射文件常用的几个顶级元素

• cache – 该命名空间的缓存配置。
  
• cache-ref – 引用别的命名空间的缓存配置。
  
• resultMap – 形貌怎样从数据库结果集中加载对象，是最复杂也是最强大的元素。
  
• parameterType - 将会传入这条语句的参数的类全限定名或别名
  
• sql – 可被别的语句引用的可重用语句块。
  
• insert – 映射插入语句。
  
• update – 映射更新语句。
  
• delete – 映射删除语句。
  
• select – 映射查询语句。
  

parameterType(输入参数类型)

• 传入简单类型，好比按照id 查Monster
  
• 传入POJO 类型，查询时必要有多个筛选条件
  
• 当有多个条件时，传入的参数就是Pojo 类型的Java 对象
  
• 当传入的参数类是String 时，也可以利用${} 来接收参数
  

1. <mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>SELECT * FROM  `monk` WHERE `nickname`  LIKE '%${name}%'

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• 传入的是List 时，resultType=“T”类型
  

1. <mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>SELECT * FROM `monk` WHERE `id` = #{id} OR `nickname` = #{nickname}

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传入HashMap

• HashMap 传入参数更加机动，好比可以机动的增长查询的属性，而不受限于Monster 这
  个Pojo 属性本身
  
• parameterType="map"
  

1. <mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>SELECT * FROM  `monk` WHERE `id` > #{id} AND `salary` > #{salary}

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传入和返回HashMap

• parameterType="map"
  
• resultType="map"
  

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/><mappers>
5.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
6. </mappers>SELECT * FROM  `monk` WHERE `id` > #{id} AND `salary` > #{salary}<mappers>
7.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
8. </mappers>

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resultMap(结果集映射)

根本介绍

​<mappers>
<mappers>
<mappers>
        <package name="com.cody_study.mapper"/>
</mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
</mappers><mapper />
</mappers>当实体类的属性和表的字段名字不一致时，我们可以通过resultMap 进行映射，从而屏蔽
实体类属性名和表的字段名的不同.（作用）
案例

1. public interface UserMapper {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>//查询所有的User<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>public List findAllUser();}

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1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/><mappers>
5.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
6. </mappers> SELECT * FROM `user`

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动态SQL语句

根本介绍

• 在一个现实的项目中，sql 语句往往是比较复杂的
  
• 为了满足更加复杂的业务需求，MyBatis 的筹划者，提供了动态天生SQL 的功能。
  
• 动态SQL 是MyBatis 的强大特性之一
  
• 利用JDBC 或别的类似的框架，根据不同条件拼接SQL 语句非常贫苦，比方拼接时要
  
• 确保不能忘记添加必要的空格，还要注意去掉列表末了一个列名的逗号等
  
• SQL 映射语句中的强大的动态SQL 语言, 可以很好的办理这个问题.
  
• 最重要的是办理一些普通的SQL无法处理的带有复杂逻辑的语句
  

动态SQL 常用标签

动态SQL 提供了如下几种常用的标签，类似我们Java 的控制语句：

• if [判定]
  
• where [拼接where 子句]
  
• choose/when/otherwise [类似java 的switch 语句, 注意是单分支]
  
• foreach [类似in ]
  
• trim [更换关键字/定制元素的功能]
  
• set [在update 的set 中，可以保证进入set 标签的属性被修改，而没有进入set 的，保
  持原来的值]
  

if [判定]

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/>SELECT * FROM `monk` WHERE 1 = 1  
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers><properties resource="jdbc.properties"/>  
11. <mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers><properties resource="jdbc.properties"/>  
14. <mappers>
15.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
16. </mappers><properties resource="jdbc.properties"/>  AND  id > #{id}  
17. <mappers>
18.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
19. </mappers><properties resource="jdbc.properties"/>  
20. <mappers>
21.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
22. </mappers><properties resource="jdbc.properties"/>

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where [拼接where 子句]

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/>SELECT * FROM `monk`  
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers><properties resource="jdbc.properties"/>  
11. <mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers><properties resource="jdbc.properties"/>  
14. <mappers>
15.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
16. </mappers><properties resource="jdbc.properties"/>  
17. <mappers>
18.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
19. </mappers><properties resource="jdbc.properties"/>  
20. <mappers>
21.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
22. </mappers><properties resource="jdbc.properties"/>  
23. <mappers>
24.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
25. </mappers><properties resource="jdbc.properties"/>AND id > #{id}  
26. <mappers>
27.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
28. </mappers><properties resource="jdbc.properties"/>  
29. <mappers>
30.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
31. </mappers><properties resource="jdbc.properties"/>  
32. <mappers>
33.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
34. </mappers><properties resource="jdbc.properties"/>  
35. <mappers>
36.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
37. </mappers><properties resource="jdbc.properties"/>  
38. <mappers>
39.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
40. </mappers><properties resource="jdbc.properties"/>  
41. <mappers>
42.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
43. </mappers><properties resource="jdbc.properties"/><mappers>
44.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
45. </mappers>AND `nickname` = #{nic kname}  
46. <mappers>
47.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
48. </mappers><properties resource="jdbc.properties"/>  
49. <mappers>
50.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
51. </mappers><properties resource="jdbc.properties"/>  
52. <mappers>
53.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
54. </mappers><properties resource="jdbc.properties"/>  
55. <mappers>
56.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
57. </mappers><properties resource="jdbc.properties"/>

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choose/when/otherwise [类似java 的switch 语句, 注意是单分支]

1. <mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>select * from `monk`  
4. <mappers>
5.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
6. </mappers><properties resource="jdbc.properties"/>  
7. <mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers><properties resource="jdbc.properties"/>  
10. <mappers>
11.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
12. </mappers><properties resource="jdbc.properties"/>  
13. <mappers>
14.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
15. </mappers><properties resource="jdbc.properties"/>where nickname = #{nickname}  
16. <mappers>
17.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
18. </mappers><properties resource="jdbc.properties"/>  
19. <mappers>
20.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
21. </mappers><properties resource="jdbc.properties"/>  
22. <mappers>
23.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
24. </mappers><properties resource="jdbc.properties"/>  
25. <mappers>
26.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
27. </mappers><properties resource="jdbc.properties"/><mappers>
28.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
29. </mappers>where id = #{id}  
30. <mappers>
31.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
32. </mappers><properties resource="jdbc.properties"/>  
33. <mappers>
34.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
35. </mappers><properties resource="jdbc.properties"/>  
36. <mappers>
37.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
38. </mappers><properties resource="jdbc.properties"/>  
39. <mappers>
40.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
41. </mappers><properties resource="jdbc.properties"/><mappers>
42.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
43. </mappers>where salary > 10000  
44. <mappers>
45.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
46. </mappers><properties resource="jdbc.properties"/>  
47. <mappers>
48.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
49. </mappers><properties resource="jdbc.properties"/>

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foreach [类似in ]

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/><mappers>
5.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
6. </mappers> SELECT * FROM `monk`  
7. <mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers><properties resource="jdbc.properties"/>  
10. <mappers>
11.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
12. </mappers><properties resource="jdbc.properties"/>  
13. <mappers>
14.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
15. </mappers><properties resource="jdbc.properties"/>  
16. <mappers>
17.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
18. </mappers><properties resource="jdbc.properties"/>  
19. <mappers>
20.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
21. </mappers><properties resource="jdbc.properties"/>  
22. <mappers>
23.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
24. </mappers><properties resource="jdbc.properties"/>id IN  
25. <mappers>
26.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
27. </mappers><properties resource="jdbc.properties"/>  
28. <mappers>
29.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
30. </mappers><properties resource="jdbc.properties"/>  
31. <mappers>
32.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
33. </mappers><properties resource="jdbc.properties"/>  
34. <mappers>
35.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
36. </mappers><properties resource="jdbc.properties"/>  
37. <mappers>
38.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
39. </mappers><properties resource="jdbc.properties"/>  
40. <mappers>
41.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
42. </mappers><properties resource="jdbc.properties"/>#{id}  
43. <mappers>
44.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
45. </mappers><properties resource="jdbc.properties"/>  
46. <mappers>
47.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
48. </mappers><properties resource="jdbc.properties"/>  
49. <mappers>
50.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
51. </mappers><properties resource="jdbc.properties"/>  
52. <mappers>
53.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
54. </mappers><properties resource="jdbc.properties"/>  
55. <mappers>
56.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
57. </mappers><properties resource="jdbc.properties"/>  
58. <mappers>
59.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
60. </mappers><properties resource="jdbc.properties"/><mappers>
61.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
62. </mappers>

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trim [更换关键字/定制元素的功能]

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/>  SELECT * FROM `monk`  
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers><properties resource="jdbc.properties"/>  
11. <mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers><properties resource="jdbc.properties"/>  
14. <mappers>
15.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
16. </mappers><properties resource="jdbc.properties"/>  
17. <mappers>
18.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
19. </mappers><properties resource="jdbc.properties"/>  
20. <mappers>
21.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
22. </mappers><properties resource="jdbc.properties"/>  
23. <mappers>
24.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
25. </mappers><properties resource="jdbc.properties"/>ZY id > #{id}  
26. <mappers>
27.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
28. </mappers><properties resource="jdbc.properties"/>  
29. <mappers>
30.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
31. </mappers><properties resource="jdbc.properties"/>  
32. <mappers>
33.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
34. </mappers><properties resource="jdbc.properties"/>  
35. <mappers>
36.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
37. </mappers><properties resource="jdbc.properties"/>  
38. <mappers>
39.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
40. </mappers><properties resource="jdbc.properties"/>  
41. <mappers>
42.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
43. </mappers><properties resource="jdbc.properties"/><mappers>
44.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
45. </mappers>AND `nickname` = #{nickname}  
46. <mappers>
47.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
48. </mappers><properties resource="jdbc.properties"/>  
49. <mappers>
50.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
51. </mappers><properties resource="jdbc.properties"/>  
52. <mappers>
53.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
54. </mappers><properties resource="jdbc.properties"/>  
55. <mappers>
56.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
57. </mappers><properties resource="jdbc.properties"/>

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set [在update 的set 中，可以保证进入set 标签的属性被修改，而没有进入set 的，保
持原来的值]

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/>UPDATE `monk`  
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers><properties resource="jdbc.properties"/>  
11. <mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers><properties resource="jdbc.properties"/>  
14. <mappers>
15.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
16. </mappers><properties resource="jdbc.properties"/>  
17. <mappers>
18.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
19. </mappers><properties resource="jdbc.properties"/>  
20. <mappers>
21.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
22. </mappers><properties resource="jdbc.properties"/>  
23. <mappers>
24.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
25. </mappers><properties resource="jdbc.properties"/>`grade` = #{grade},  
26. <mappers>
27.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
28. </mappers><properties resource="jdbc.properties"/>  
29. <mappers>
30.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
31. </mappers><properties resource="jdbc.properties"/>  
32. <mappers>
33.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
34. </mappers><properties resource="jdbc.properties"/>  
35. <mappers>
36.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
37. </mappers><properties resource="jdbc.properties"/>  
38. <mappers>
39.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
40. </mappers><properties resource="jdbc.properties"/>  
41. <mappers>
42.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
43. </mappers><properties resource="jdbc.properties"/><mappers>
44.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
45. </mappers>`skill` = #{skill},  
46. <mappers>
47.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
48. </mappers><properties resource="jdbc.properties"/>  
49. <mappers>
50.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
51. </mappers><properties resource="jdbc.properties"/>  
52. <mappers>
53.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
54. </mappers><properties resource="jdbc.properties"/>  
55. <mappers>
56.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
57. </mappers><properties resource="jdbc.properties"/>  
58. <mappers>
59.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
60. </mappers><properties resource="jdbc.properties"/>  
61. <mappers>
62.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
63. </mappers><properties resource="jdbc.properties"/><mappers>
64.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
65. </mappers>`nickname` = #{nickname},  
66. <mappers>
67.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
68. </mappers><properties resource="jdbc.properties"/>  
69. <mappers>
70.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
71. </mappers><properties resource="jdbc.properties"/>  
72. <mappers>
73.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
74. </mappers><properties resource="jdbc.properties"/>  
75. <mappers>
76.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
77. </mappers><properties resource="jdbc.properties"/>  
78. <mappers>
79.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
80. </mappers><properties resource="jdbc.properties"/>  
81. <mappers>
82.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
83. </mappers><properties resource="jdbc.properties"/><mappers>
84.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
85. </mappers>`grade` = #{grade},  
86. <mappers>
87.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
88. </mappers><properties resource="jdbc.properties"/>  
89. <mappers>
90.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
91. </mappers><properties resource="jdbc.properties"/>  
92. <mappers>
93.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
94. </mappers><properties resource="jdbc.properties"/>  
95. <mappers>
96.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
97. </mappers><properties resource="jdbc.properties"/>  
98. <mappers>
99.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
100. </mappers><properties resource="jdbc.properties"/>  
101. <mappers>
102.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
103. </mappers><properties resource="jdbc.properties"/><mappers>
104.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
105. </mappers>`salary` = #{salary},  
106. <mappers>
107.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
108. </mappers><properties resource="jdbc.properties"/>  
109. <mappers>
110.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
111. </mappers><properties resource="jdbc.properties"/>  
112. <mappers>
113.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
114. </mappers><properties resource="jdbc.properties"/>  
115. <mappers>
116.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
117. </mappers><properties resource="jdbc.properties"/>  
118. <mappers>
119.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
120. </mappers><properties resource="jdbc.properties"/>  
121. <mappers>
122.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
123. </mappers><properties resource="jdbc.properties"/><mappers>
124.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
125. </mappers>`birthTime` = #{birthTime},  
126. <mappers>
127.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
128. </mappers><properties resource="jdbc.properties"/>  
129. <mappers>
130.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
131. </mappers><properties resource="jdbc.properties"/>  
132. <mappers>
133.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
134. </mappers><properties resource="jdbc.properties"/>  
135. <mappers>
136.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
137. </mappers><properties resource="jdbc.properties"/>  
138. <mappers>
139.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
140. </mappers><properties resource="jdbc.properties"/>  
141. <mappers>
142.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
143. </mappers><properties resource="jdbc.properties"/><mappers>
144.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
145. </mappers>`entry` = #{entry},  
146. <mappers>
147.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
148. </mappers><properties resource="jdbc.properties"/>  
149. <mappers>
150.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
151. </mappers><properties resource="jdbc.properties"/>  
152. <mappers>
153.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
154. </mappers><properties resource="jdbc.properties"/>  
155. <mappers>
156.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
157. </mappers><properties resource="jdbc.properties"/><mappers>
158.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
159. </mappers>WHERE id = #{id}<mappers>
160.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
161. </mappers>

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映射关系一对一

根本介绍

• 项目中1 对1 的关系是一个根本的映射关系，好比erson(人) --- IDCard(身份证
  

映射方式

• 通过配置XxxMapper.xml 实现1 对1 [配置方式]
  
• 通过注解的方式实现1 对1 [注解方式]
  

映射方式一：配置Mapper.xml实现

• 通过配置XxxMapper.xml 的方式，实现级联查询，通过person 可以获取到对应的idencard 信息
  

接口：

1. public interface PersonMapper {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>//通过Person 的id 获取到Person,包括这个Person 关联的IdenCard 对象<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>Person getPersonById(Integer id);<mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers>//通过Person 的id 获取到Person,包括这个Person 管理的IdenCard 对象,方式2<mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>Person getPersonById2(Integer id);<mappers>
10.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
11. </mappers>//通过Person 的id 获取到Person<mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers>Person getPerson(Integer id);}

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1. public interface IdenCardMapper {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>//根据id 获取到身份证序列号<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>IdenCard getIdenCardById(Integer id);<mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers>//通过IdenCard 的id 获取到Person<mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>IdenCard getIdenCardAndPerson(Integer id);}

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mapper.xml：
通过person 可以获取到对应的idencard 信息
方式一 ：多表联查

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/>  
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers><properties resource="jdbc.properties"/>  
11. <mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers><properties resource="jdbc.properties"/>  
14. <mappers>
15.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
16. </mappers><properties resource="jdbc.properties"/>  
17. <mappers>
18.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
19. </mappers><properties resource="jdbc.properties"/>  
20. <mappers>
21.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
22. </mappers><properties resource="jdbc.properties"/>  
23. <mappers>
24.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
25. </mappers><properties resource="jdbc.properties"/>  
26. <mappers>
27.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
28. </mappers><properties resource="jdbc.properties"/>  select *<mappers>
29.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
30. </mappers>from `person` join `idencard` on person.card_id = idencard.id<mappers>
31.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
32. </mappers>where person.id = #{id}

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方式二：分解成单表操纵

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/><mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>SELECT * FROM `person` where `id` = #{id}

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映射方式二：注解实现

1. public interface PersonMapperAnnotation {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>@Select(value = "SELECT * FROM `person` where `id` = #{id}")<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>@Results({  
6. <mappers>
7.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
8. </mappers><properties resource="jdbc.properties"/>  
9. <mappers>
10.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
11. </mappers><properties resource="jdbc.properties"/>@Result(id = true,property = "id",column = "id"),  
12. <mappers>
13.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
14. </mappers><properties resource="jdbc.properties"/>  
15. <mappers>
16.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
17. </mappers><properties resource="jdbc.properties"/>@Result(property = "name",column = "name"),  
18. <mappers>
19.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
20. </mappers><properties resource="jdbc.properties"/>  
21. <mappers>
22.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
23. </mappers><properties resource="jdbc.properties"/>@Result(property = "card",column = "card_id",  
24. <mappers>
25.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
26. </mappers><properties resource="jdbc.properties"/>  
27. <mappers>
28.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
29. </mappers><properties resource="jdbc.properties"/>  
30. <mappers>
31.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
32. </mappers><properties resource="jdbc.properties"/>  one = @One(select = "com.code_study.mapper.IdenCardMapperAnnotation.getIdenCardById"))<mappers>
33.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
34. </mappers>})<mappers>
35.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
36. </mappers>Person getPersonById(Integer id);}

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映射关系多对一

根本介绍

• 项目中多对1 的关系是一个根本的映射关系, 多对1, 也可以理解成是1 对多.
  
• User --- Pet： 一个用户可以养多只宠物
  
• Dep ---Emp : 一个部门可以有多个员工
  

映射方式

• 通过配置XxxMapper.xml 实现1 对1 [配置方式]
  
• 通过注解的方式实现1 对1 [注解方式]
  

映射方式一：配置Mapper.xml实现

接口：

1. public interface UserMapper {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>//通过id 获取User 对象<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>public User getUserById(Integer id);}

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1. public interface PetMapper {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>//通过User 的id 来获取pet 对象，可能有多个，因此利用List 接收<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>public List getPetByUserId(Integer userId);<mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers>//通过pet 的id 获取Pet 对象<mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>public Pet getPetById(Integer id);}

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mapper.xml

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/>  
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers><properties resource="jdbc.properties"/>  
11. <mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers><properties resource="jdbc.properties"/>  
14. <mappers>
15.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
16. </mappers><properties resource="jdbc.properties"/>  
17. <mappers>
18.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
19. </mappers><properties resource="jdbc.properties"/>  
20. <mappers>
21.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
22. </mappers><properties resource="jdbc.properties"/> SELECT * FROM `mybatis_pet` WHERE user_id = #{userId}  
23. <mappers>
24.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
25. </mappers><properties resource="jdbc.properties"/>  
26. <mappers>
27.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
28. </mappers><properties resource="jdbc.properties"/>  
29. <mappers>
30.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
31. </mappers><properties resource="jdbc.properties"/>  
32. <mappers>
33.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
34. </mappers><properties resource="jdbc.properties"/>select * from `mybatis_pet` where id = #{id}<mappers>
35.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
36. </mappers>

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1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/><mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>SELECT * from `mybatis_user` WHERE id = #{id}

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说明：

• 多对一时，resultMap中 collection 标签表示集合
  
• 在 collection 标签中 属性 ofType 表示集合中存放的数据类型
  
• 双向多对一时，toString应该去掉，避免栈溢出
  
• resultMap中 select 标签表示复用这个目的方法，推荐利用，这样提高代码的复用性，将多表拆解成单表
  

映射方式二：注解实现

1. public interface UserMapperAnnotation {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>//通过id 获取User 对象  
4. <mappers>
5.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
6. </mappers><properties resource="jdbc.properties"/> @Select(value = "SELECT * from `mybatis_user` WHERE id = #{id}")<mappers>
7.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
8. </mappers>@Results({  
9. <mappers>
10.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
11. </mappers><properties resource="jdbc.properties"/>  
12. <mappers>
13.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
14. </mappers><properties resource="jdbc.properties"/>@Result(id = true,property = "id",column = "id"),  
15. <mappers>
16.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
17. </mappers><properties resource="jdbc.properties"/>  
18. <mappers>
19.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
20. </mappers><properties resource="jdbc.properties"/>@Result(property = "name",column = "name"),  
21. <mappers>
22.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
23. </mappers><properties resource="jdbc.properties"/>  
24. <mappers>
25.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
26. </mappers><properties resource="jdbc.properties"/>@Result(property = "pets",column = "id",  
27. <mappers>
28.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
29. </mappers><properties resource="jdbc.properties"/>  
30. <mappers>
31.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
32. </mappers><properties resource="jdbc.properties"/>  
33. <mappers>
34.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
35. </mappers><properties resource="jdbc.properties"/>  many = @Many(select = "com.code_study.mapper.PetMapperAnnotation.getPetByUserId"))<mappers>
36.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
37. </mappers>})<mappers>
38.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
39. </mappers>public User getUserById(Integer id);}

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1. public interface PetMapperAnnotation {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>//通过User 的id 来获取pet 对象，可能有多个，因此利用List 接收<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>@Select(value = "SELECT * FROM `mybatis_pet` WHERE user_id = #{userId}")<mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers>@Results(id = "PetResultMap",value = {  
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers><properties resource="jdbc.properties"/>  
11. <mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers><properties resource="jdbc.properties"/>@Result(id = true,property = "id",column = "id"),  
14. <mappers>
15.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
16. </mappers><properties resource="jdbc.properties"/>  
17. <mappers>
18.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
19. </mappers><properties resource="jdbc.properties"/>@Result(property = "nickname",column = "nickname"),  
20. <mappers>
21.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
22. </mappers><properties resource="jdbc.properties"/>  
23. <mappers>
24.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
25. </mappers><properties resource="jdbc.properties"/>@Result(property = "user",column = "user_id",  
26. <mappers>
27.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
28. </mappers><properties resource="jdbc.properties"/>  
29. <mappers>
30.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
31. </mappers><properties resource="jdbc.properties"/>  
32. <mappers>
33.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
34. </mappers><properties resource="jdbc.properties"/>  one = @One(select = "com.code_study.mapper.UserMapperAnnotation.getUserById"))<mappers>
35.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
36. </mappers>})<mappers>
37.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
38. </mappers>List getPetByUserId(Integer userId);<mappers>
39.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
40. </mappers>//通过pet 的id 获取Pet 对象<mappers>
41.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
42. </mappers>@Select(value = " select * from `mybatis_pet` where id = #{id}")<mappers>
43.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
44. </mappers>@ResultMap(value = "PetResultMap")<mappers>
45.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
46. </mappers>Pet getPetById(Integer id);}

复制代码

• @Results(id = "etResultMap"...)可以给@Results设置一个 id 用来复用代码
  
• 在下面就进行了@Results 的复用
  

1. //通过pet 的id 获取Pet 对象   <mappers>
2. <mappers>
3. <mappers>
4.         <package name="com.cody_study.mapper"/>
5. </mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
6. </mappers><mapper />
7. </mappers>@Select(value = " select * from `mybatis_pet` where id = #{id}") <mappers>
8. <mappers>
9. <mappers>
10.         <package name="com.cody_study.mapper"/>
11. </mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
12. </mappers><mapper />
13. </mappers>@ResultMap(value = "PetResultMap")<mappers>
14.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
15. </mappers>Pet getPetById(Integer id);

复制代码

MyBatis缓存

根本介绍

• MyBatis 内置了一个强大的事务性查询缓存机制，它可以非常方便地配置和定制。
  

相关文档

一级缓存

• 默认情况下，mybatis 是启用一级缓存的/本地缓存/local Cache，它是SqlSession 级别的。
  
• 同一个SqlSession 接口对象调用了雷同的select 语句,会直接从缓存里面获取，而不是再
  去查询数据库
  

一级缓存原理图

一级缓存失效的情况

• 关闭sqlSession 会话后, 再次查询，会到数据库查询
  
• 当实行sqlSession.clearCache() 会使一级缓存失效
  
• 当对同一个monster 修改，该对象在一级缓存会失效
  

二级缓存

• 二级缓存和一级缓存都是为了提高检索服从的技能
  
• 最大的区别就是作用域的范围不一样，一级缓存的作用域是sqlSession 会话级别,在一次
  会话有效，而二级缓存作用域是全局范围，针对不同的会话都有效
  

二级缓存原理图

二级缓存配置

​<mappers>
<mappers>
<mappers>
        <package name="com.cody_study.mapper"/>
</mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
</mappers><mapper />
</mappers>1.在mybatis-config.xml中 全局性的开启缓存
​<mappers>
    <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
</mappers>
​<mappers>
    <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
</mappers>

​<mappers>
<mappers>
<mappers>
        <package name="com.cody_study.mapper"/>
</mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
</mappers><mapper />
</mappers>2.利用二级缓存时entity 类实现序列化接口(serializable)，由于二级缓存可能利用到序列化技能
​<mappers>
<mappers>
<mappers>
        <package name="com.cody_study.mapper"/>
</mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
</mappers><mapper />
</mappers><mappers>
<mappers>
<mappers>
        <package name="com.cody_study.mapper"/>
</mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
</mappers><mapper />
</mappers>*大部分情况不必要这样配置，只是某些第三方缓存库必要序列化到磁盘！
​<mappers>
<mappers>
<mappers>
        <package name="com.cody_study.mapper"/>
</mappers><mapper url="file:///D:\yy\kk\yy\MOnsterMapper.xml" />
</mappers><mapper />
</mappers>3.再对应的XxxMapper.xml中设置二级缓存的计谋

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/>  
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers><properties resource="jdbc.properties"/>   SELECT * FROM `monster` WHERE id = #{id}<mappers>
11.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
12. </mappers>

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注意事项

• 表示创建了FIFO 的计谋，每隔30 秒刷新一次，最多存放360 个对象而且返回的对象被认为是只读的。
  
• eviction：缓存的回收计谋
  
• flushInterval:时间隔断，单位是毫秒，
  
• size：引用数目，内存大就多配置点，要记住你缓存的对象数目和你运行环境的可用内存
  
• 资源数目。默认值是1024
  
• readOnly:true,只读
  

四大计谋

• LRU – 最近最少利用：移除最长时间不被利用的对象。
  
• FIFO – 先进先出：按对象进入缓存的顺序来移除它们。
  
• SOFT – 软引用：基于垃圾回收器状态和软引用规则移除对象。
  
• WEAK – 弱引用：更积极地基于垃圾收集器状态和弱引用规则移除对象
  

怎样禁用二级缓存

方式一

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  

复制代码

方式二

在XxxMapper.xml文件中不配做
方式三

直接在XxxMapper.xml文件对应的方法上 设置属性 useCache=false

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/>   SELECT * FROM `monster`<mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>

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一级缓存和二级缓存的实行顺序

• 缓存实行顺序是：二级缓存-->一级缓存-->数据库
  
• 当我们关闭了一级缓存的时候，如果配置了二级缓存，那么一级缓存的数据会放入二级缓存中
  
• 不会出现一级缓存和二级缓存中有同一个数据。由于二级缓存(数据)是在一级缓存关闭之后才有的
  

第三方缓存框架---EhCache

根本介绍

• EhCache 是一个纯Java 的缓存框架，具有快速、精干等特点
  
• MyBatis 有本身默认的二级缓存(前面我们已经利用过了)，但是在现实项目中，往往利用
  的是更加专业的第三方缓存产品作为MyBatis 的二级缓存,EhCache 就是非常优秀的缓存
  产品
  

配置利用第三方缓存框架

添加依赖

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/>net.sf.ehcache  
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers><properties resource="jdbc.properties"/>  ehcache-core  
11. <mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers><properties resource="jdbc.properties"/>  2.6.11  
14. <mappers>
15.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
16. </mappers><properties resource="jdbc.properties"/>  
17. <mappers>
18.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
19. </mappers><properties resource="jdbc.properties"/><mappers>
20.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
21. </mappers>org.slf4j  
22. <mappers>
23.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
24. </mappers><properties resource="jdbc.properties"/>  slf4j-api  
25. <mappers>
26.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
27. </mappers><properties resource="jdbc.properties"/>  1.7.25  
28. <mappers>
29.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
30. </mappers><properties resource="jdbc.properties"/>  
31. <mappers>
32.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
33. </mappers><properties resource="jdbc.properties"/><mappers>
34.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
35. </mappers>org.mybatis.caches  
36. <mappers>
37.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
38. </mappers><properties resource="jdbc.properties"/>  mybatis-ehcache  
39. <mappers>
40.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
41. </mappers><properties resource="jdbc.properties"/>  1.2.1<mappers>
42.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
43. </mappers>

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在XxxMapper.xml文件中启用EhCache

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/>  
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers><properties resource="jdbc.properties"/>  
11. <mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers><properties resource="jdbc.properties"/> SELECT * FROM `monster` WHERE id = #{id}<mappers>
14.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
15. </mappers>

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怎样理解EhCache 和MyBatis 缓存的关系

• MyBatis 提供了一个接口Cacheorg.apache.ibatis.cache.Cache
  
• 只要实现了该Cache 接口，就可以作为二级缓存产品和MyBatis 整合利用,Ehcache 就
  是实现了该接口
  
• MyBatis 默认情况(即一级缓存)是利用的PerpetualCache 类实现Cache 接口的,是焦点类
  
• 当我们利用了Ehcahce 后，就是EhcacheCache 类实现Cache 接口的，是焦点类.
  
• 缓存的本质就是Map
  

手写MyBatis底层机制

读取配置文件，得到数据库连接

思绪

• 引入必要的依赖
  
• 必要写一个本身的config.xml文件，在里面配置一些信息，driver，url ，password，username
  
• 必要编写Configuration类，对 本身的config.xml文件 进行解析，得到一个数据库连接
  

实现

• 引入必要的依赖
  

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/>  
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers><properties resource="jdbc.properties"/>  dom4j  
11. <mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers><properties resource="jdbc.properties"/>  
14. <mappers>
15.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
16. </mappers><properties resource="jdbc.properties"/>dom4j  
17. <mappers>
18.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
19. </mappers><properties resource="jdbc.properties"/>  
20. <mappers>
21.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
22. </mappers><properties resource="jdbc.properties"/>1.6.1  
23. <mappers>
24.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
25. </mappers><properties resource="jdbc.properties"/>  
26. <mappers>
27.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
28. </mappers><properties resource="jdbc.properties"/>  
29. <mappers>
30.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
31. </mappers><properties resource="jdbc.properties"/>  
32. <mappers>
33.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
34. </mappers><properties resource="jdbc.properties"/><mappers>
35.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
36. </mappers>mysql  
37. <mappers>
38.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
39. </mappers><properties resource="jdbc.properties"/>  
40. <mappers>
41.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
42. </mappers><properties resource="jdbc.properties"/>mysql-connector-java  
43. <mappers>
44.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
45. </mappers><properties resource="jdbc.properties"/>  
46. <mappers>
47.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
48. </mappers><properties resource="jdbc.properties"/>5.1.49  
49. <mappers>
50.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
51. </mappers><properties resource="jdbc.properties"/>  
52. <mappers>
53.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
54. </mappers><properties resource="jdbc.properties"/>  
55. <mappers>
56.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
57. </mappers><properties resource="jdbc.properties"/>  
58. <mappers>
59.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
60. </mappers><properties resource="jdbc.properties"/><mappers>
61.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
62. </mappers>org.projectlombok  
63. <mappers>
64.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
65. </mappers><properties resource="jdbc.properties"/>  
66. <mappers>
67.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
68. </mappers><properties resource="jdbc.properties"/>lombok  
69. <mappers>
70.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
71. </mappers><properties resource="jdbc.properties"/>  
72. <mappers>
73.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
74. </mappers><properties resource="jdbc.properties"/>1.18.4  
75. <mappers>
76.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
77. </mappers><properties resource="jdbc.properties"/>  
78. <mappers>
79.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
80. </mappers><properties resource="jdbc.properties"/>  
81. <mappers>
82.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
83. </mappers><properties resource="jdbc.properties"/>  
84. <mappers>
85.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
86. </mappers><properties resource="jdbc.properties"/><mappers>
87.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
88. </mappers>junit  
89. <mappers>
90.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
91. </mappers><properties resource="jdbc.properties"/>  
92. <mappers>
93.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
94. </mappers><properties resource="jdbc.properties"/>junit  
95. <mappers>
96.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
97. </mappers><properties resource="jdbc.properties"/>  
98. <mappers>
99.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
100. </mappers><properties resource="jdbc.properties"/>4.12  
101. <mappers>
102.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
103. </mappers><properties resource="jdbc.properties"/>  
104. <mappers>
105.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
106. </mappers><properties resource="jdbc.properties"/>

复制代码

• 必要写一个本身的config.xml文件，在里面配置一些信息，driver，url ，password，username
  

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/><mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>

复制代码

• 必要编写Configuration类，对 本身的config.xml文件 进行解析，得到一个数据库连接
  

1. public class ZyConfiguration {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>//属性 类加载器<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>private ClassLoader classLoader =  
6. <mappers>
7.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
8. </mappers><properties resource="jdbc.properties"/>  
9. <mappers>
10.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
11. </mappers><properties resource="jdbc.properties"/>ClassLoader.getSystemClassLoader();<mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers>//读取xml文件信息并处理<mappers>
14.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
15. </mappers>public Connection build(String resource) {  
16. <mappers>
17.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
18. </mappers><properties resource="jdbc.properties"/>  Connection connection = null;  
19. <mappers>
20.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
21. </mappers><properties resource="jdbc.properties"/>  
22. <mappers>
23.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
24. </mappers><properties resource="jdbc.properties"/><mappers>
25.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
26. </mappers>//加载配置文件，获取对应的InputStream流  
27. <mappers>
28.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
29. </mappers><properties resource="jdbc.properties"/>  InputStream resourceAsStream =  
30. <mappers>
31.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
32. </mappers><properties resource="jdbc.properties"/>  
33. <mappers>
34.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
35. </mappers><properties resource="jdbc.properties"/><mappers>
36.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
37. </mappers>classLoader.getResourceAsStream(resource);  
38. <mappers>
39.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
40. </mappers><properties resource="jdbc.properties"/>  //解析xml文件  
41. <mappers>
42.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
43. </mappers><properties resource="jdbc.properties"/>  SAXReader reader = new SAXReader();  
44. <mappers>
45.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
46. </mappers><properties resource="jdbc.properties"/>  try {  
47. <mappers>
48.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
49. </mappers><properties resource="jdbc.properties"/>  
50. <mappers>
51.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
52. </mappers><properties resource="jdbc.properties"/>Document document = reader.read(resourceAsStream);  
53. <mappers>
54.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
55. </mappers><properties resource="jdbc.properties"/>  
56. <mappers>
57.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
58. </mappers><properties resource="jdbc.properties"/>Element root = document.getRootElement();  
59. <mappers>
60.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
61. </mappers><properties resource="jdbc.properties"/>  
62. <mappers>
63.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
64. </mappers><properties resource="jdbc.properties"/>//解析rootElement  
65. <mappers>
66.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
67. </mappers><properties resource="jdbc.properties"/>  
68. <mappers>
69.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
70. </mappers><properties resource="jdbc.properties"/>System.out.println("root= "+root);  
71. <mappers>
72.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
73. </mappers><properties resource="jdbc.properties"/>  
74. <mappers>
75.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
76. </mappers><properties resource="jdbc.properties"/>return evalDataSource(root);  
77. <mappers>
78.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
79. </mappers><properties resource="jdbc.properties"/>  } catch (DocumentException e) {  
80. <mappers>
81.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
82. </mappers><properties resource="jdbc.properties"/>  
83. <mappers>
84.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
85. </mappers><properties resource="jdbc.properties"/>throw new RuntimeException(e);  
86. <mappers>
87.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
88. </mappers><properties resource="jdbc.properties"/>  }<mappers>
89.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
90. </mappers>}<mappers>
91.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
92. </mappers>//解析xml文件 并返回一个连接<mappers>
93.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
94. </mappers>private Connection evalDataSource(Element node) {  
95. <mappers>
96.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
97. </mappers><properties resource="jdbc.properties"/>  Iterator property = node.elementIterator("property");  
98. <mappers>
99.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
100. </mappers><properties resource="jdbc.properties"/>  String driverClassName = null;  
101. <mappers>
102.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
103. </mappers><properties resource="jdbc.properties"/>  String url = null;  
104. <mappers>
105.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
106. </mappers><properties resource="jdbc.properties"/>  String username = null;  
107. <mappers>
108.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
109. </mappers><properties resource="jdbc.properties"/>  String password = null;  
110. <mappers>
111.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
112. </mappers><properties resource="jdbc.properties"/>  //遍历node子节点 获取属性值  
113. <mappers>
114.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
115. </mappers><properties resource="jdbc.properties"/>  while(property.hasNext()){  
116. <mappers>
117.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
118. </mappers><properties resource="jdbc.properties"/>  
119. <mappers>
120.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
121. </mappers><properties resource="jdbc.properties"/>Element pro = (Element)property.next();  
122. <mappers>
123.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
124. </mappers><properties resource="jdbc.properties"/>  
125. <mappers>
126.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
127. </mappers><properties resource="jdbc.properties"/>String name = pro.attributeValue("name");  
128. <mappers>
129.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
130. </mappers><properties resource="jdbc.properties"/>  
131. <mappers>
132.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
133. </mappers><properties resource="jdbc.properties"/>String value = pro.attributeValue("value");  
134. <mappers>
135.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
136. </mappers><properties resource="jdbc.properties"/>  
137. <mappers>
138.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
139. </mappers><properties resource="jdbc.properties"/>//判定是否得到了name 和 value  
140. <mappers>
141.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
142. </mappers><properties resource="jdbc.properties"/>  
143. <mappers>
144.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
145. </mappers><properties resource="jdbc.properties"/>if (name == null || value == null){  
146. <mappers>
147.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
148. </mappers><properties resource="jdbc.properties"/>  
149. <mappers>
150.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
151. </mappers><properties resource="jdbc.properties"/><mappers>
152.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
153. </mappers>throw new RuntimeException("property 节点没有设置name 或 value属性");  
154. <mappers>
155.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
156. </mappers><properties resource="jdbc.properties"/>  
157. <mappers>
158.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
159. </mappers><properties resource="jdbc.properties"/>}  
160. <mappers>
161.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
162. </mappers><properties resource="jdbc.properties"/>  
163. <mappers>
164.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
165. </mappers><properties resource="jdbc.properties"/>switch (name){  
166. <mappers>
167.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
168. </mappers><properties resource="jdbc.properties"/>  
169. <mappers>
170.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
171. </mappers><properties resource="jdbc.properties"/><mappers>
172.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
173. </mappers>case "driverClassName":  
174. <mappers>
175.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
176. </mappers><properties resource="jdbc.properties"/>  
177. <mappers>
178.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
179. </mappers><properties resource="jdbc.properties"/>  
180. <mappers>
181.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
182. </mappers><properties resource="jdbc.properties"/>  driverClassName = value;  
183. <mappers>
184.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
185. </mappers><properties resource="jdbc.properties"/>  
186. <mappers>
187.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
188. </mappers><properties resource="jdbc.properties"/>  
189. <mappers>
190.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
191. </mappers><properties resource="jdbc.properties"/>  break;  
192. <mappers>
193.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
194. </mappers><properties resource="jdbc.properties"/>  
195. <mappers>
196.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
197. </mappers><properties resource="jdbc.properties"/><mappers>
198.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
199. </mappers>case "url":  
200. <mappers>
201.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
202. </mappers><properties resource="jdbc.properties"/>  
203. <mappers>
204.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
205. </mappers><properties resource="jdbc.properties"/>  
206. <mappers>
207.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
208. </mappers><properties resource="jdbc.properties"/>  url = value;  
209. <mappers>
210.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
211. </mappers><properties resource="jdbc.properties"/>  
212. <mappers>
213.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
214. </mappers><properties resource="jdbc.properties"/>  
215. <mappers>
216.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
217. </mappers><properties resource="jdbc.properties"/>  break;  
218. <mappers>
219.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
220. </mappers><properties resource="jdbc.properties"/>  
221. <mappers>
222.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
223. </mappers><properties resource="jdbc.properties"/><mappers>
224.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
225. </mappers>case "username":  
226. <mappers>
227.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
228. </mappers><properties resource="jdbc.properties"/>  
229. <mappers>
230.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
231. </mappers><properties resource="jdbc.properties"/>  
232. <mappers>
233.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
234. </mappers><properties resource="jdbc.properties"/>  username = value;  
235. <mappers>
236.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
237. </mappers><properties resource="jdbc.properties"/>  
238. <mappers>
239.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
240. </mappers><properties resource="jdbc.properties"/>  
241. <mappers>
242.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
243. </mappers><properties resource="jdbc.properties"/>  break;  
244. <mappers>
245.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
246. </mappers><properties resource="jdbc.properties"/>  
247. <mappers>
248.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
249. </mappers><properties resource="jdbc.properties"/><mappers>
250.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
251. </mappers>case "password":  
252. <mappers>
253.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
254. </mappers><properties resource="jdbc.properties"/>  
255. <mappers>
256.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
257. </mappers><properties resource="jdbc.properties"/>  
258. <mappers>
259.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
260. </mappers><properties resource="jdbc.properties"/>  password = value;  
261. <mappers>
262.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
263. </mappers><properties resource="jdbc.properties"/>  
264. <mappers>
265.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
266. </mappers><properties resource="jdbc.properties"/>  
267. <mappers>
268.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
269. </mappers><properties resource="jdbc.properties"/>  break;  
270. <mappers>
271.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
272. </mappers><properties resource="jdbc.properties"/>  
273. <mappers>
274.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
275. </mappers><properties resource="jdbc.properties"/><mappers>
276.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
277. </mappers>default:  
278. <mappers>
279.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
280. </mappers><properties resource="jdbc.properties"/>  
281. <mappers>
282.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
283. </mappers><properties resource="jdbc.properties"/>  
284. <mappers>
285.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
286. </mappers><properties resource="jdbc.properties"/>  throw new RuntimeException("属性名没有匹配到");  
287. <mappers>
288.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
289. </mappers><properties resource="jdbc.properties"/>  
290. <mappers>
291.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
292. </mappers><properties resource="jdbc.properties"/>}  
293. <mappers>
294.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
295. </mappers><properties resource="jdbc.properties"/>  }  
296. <mappers>
297.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
298. </mappers><properties resource="jdbc.properties"/>  Connection connection = null;  
299. <mappers>
300.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
301. </mappers><properties resource="jdbc.properties"/>  try {  
302. <mappers>
303.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
304. </mappers><properties resource="jdbc.properties"/>  
305. <mappers>
306.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
307. </mappers><properties resource="jdbc.properties"/>Class.forName(driverClassName);  
308. <mappers>
309.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
310. </mappers><properties resource="jdbc.properties"/>  
311. <mappers>
312.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
313. </mappers><properties resource="jdbc.properties"/>connection = DriverManager.getConnection(url, username, password);  
314. <mappers>
315.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
316. </mappers><properties resource="jdbc.properties"/>  } catch (Exception e) {  
317. <mappers>
318.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
319. </mappers><properties resource="jdbc.properties"/>  
320. <mappers>
321.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
322. </mappers><properties resource="jdbc.properties"/>throw new RuntimeException(e);  
323. <mappers>
324.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
325. </mappers><properties resource="jdbc.properties"/>  }  
326. <mappers>
327.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
328. </mappers><properties resource="jdbc.properties"/>  return connection;<mappers>
329.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
330. </mappers>}}

复制代码

编写实行器，输入SQL语句，完成操纵

思绪

• 必要写一个实体类，对应monster表
  
• 编写接口executor
  
• 实现接口，编写本身的实行器
  
• 必要一个 本身的Configuration类 返回连接，通过连接对数据库进行操纵
  

实现

• 必要写一个实体类，对应monster表
  

1. @Setter@Getter@ToString@NoArgsConstructor@AllArgsConstructorpublic class Monster {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>private Integer id;<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>private Integer age;<mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers>private String name;<mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>private String email;<mappers>
10.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
11. </mappers>private Date birthday;<mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers>private double salary;<mappers>
14.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
15. </mappers>private Integer gender;}

复制代码

• 编写接口executor
  

1. public interface Executor {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>public  T query(String statement,Object parameter);}

复制代码

• 实现接口，编写本身的实行器
  

1. public class ZyExecutor implements Executor{<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>private ZyConfiguration zyConfiguration = new ZyConfiguration();<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>@Override<mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers>public  T query(String sql, Object parameter) {  
8. <mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers><properties resource="jdbc.properties"/>  Connection connection = getConnection();  
11. <mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers><properties resource="jdbc.properties"/>  //查询返回的结果集  
14. <mappers>
15.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
16. </mappers><properties resource="jdbc.properties"/>  ResultSet set = null;  
17. <mappers>
18.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
19. </mappers><properties resource="jdbc.properties"/>  PreparedStatement pre = null;  
20. <mappers>
21.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
22. </mappers><properties resource="jdbc.properties"/>  try {  
23. <mappers>
24.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
25. </mappers><properties resource="jdbc.properties"/>  
26. <mappers>
27.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
28. </mappers><properties resource="jdbc.properties"/>pre = connection.prepareStatement(sql);  
29. <mappers>
30.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
31. </mappers><properties resource="jdbc.properties"/>  
32. <mappers>
33.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
34. </mappers><properties resource="jdbc.properties"/>//设置参数，如果参数多，用数组处理  
35. <mappers>
36.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
37. </mappers><properties resource="jdbc.properties"/>  
38. <mappers>
39.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
40. </mappers><properties resource="jdbc.properties"/>pre.setString(1, parameter.toString());  
41. <mappers>
42.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
43. </mappers><properties resource="jdbc.properties"/>  
44. <mappers>
45.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
46. </mappers><properties resource="jdbc.properties"/>set = pre.executeQuery();  
47. <mappers>
48.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
49. </mappers><properties resource="jdbc.properties"/>  
50. <mappers>
51.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
52. </mappers><properties resource="jdbc.properties"/>//把set数据封装到对象 -- monster  
53. <mappers>
54.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
55. </mappers><properties resource="jdbc.properties"/>  
56. <mappers>
57.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
58. </mappers><properties resource="jdbc.properties"/>Monster monster = new Monster();//简化处理 认为返回的结果就是一个monster记录  
59. <mappers>
60.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
61. </mappers><properties resource="jdbc.properties"/>  
62. <mappers>
63.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
64. </mappers><properties resource="jdbc.properties"/>//遍历结果集  
65. <mappers>
66.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
67. </mappers><properties resource="jdbc.properties"/>  
68. <mappers>
69.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
70. </mappers><properties resource="jdbc.properties"/>while(set.next()){  
71. <mappers>
72.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
73. </mappers><properties resource="jdbc.properties"/>  
74. <mappers>
75.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
76. </mappers><properties resource="jdbc.properties"/><mappers>
77.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
78. </mappers>monster.setId(set.getInt("id"));  
79. <mappers>
80.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
81. </mappers><properties resource="jdbc.properties"/>  
82. <mappers>
83.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
84. </mappers><properties resource="jdbc.properties"/><mappers>
85.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
86. </mappers>monster.setName(set.getString("name"));  
87. <mappers>
88.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
89. </mappers><properties resource="jdbc.properties"/>  
90. <mappers>
91.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
92. </mappers><properties resource="jdbc.properties"/><mappers>
93.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
94. </mappers>monster.setEmail(set.getString("email"));  
95. <mappers>
96.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
97. </mappers><properties resource="jdbc.properties"/>  
98. <mappers>
99.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
100. </mappers><properties resource="jdbc.properties"/><mappers>
101.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
102. </mappers>monster.setAge(set.getInt("age"));  
103. <mappers>
104.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
105. </mappers><properties resource="jdbc.properties"/>  
106. <mappers>
107.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
108. </mappers><properties resource="jdbc.properties"/><mappers>
109.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
110. </mappers>monster.setGender(set.getInt("gender"));  
111. <mappers>
112.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
113. </mappers><properties resource="jdbc.properties"/>  
114. <mappers>
115.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
116. </mappers><properties resource="jdbc.properties"/><mappers>
117.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
118. </mappers>monster.setBirthday(set.getDate("birthday"));  
119. <mappers>
120.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
121. </mappers><properties resource="jdbc.properties"/>  
122. <mappers>
123.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
124. </mappers><properties resource="jdbc.properties"/><mappers>
125.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
126. </mappers>monster.setSalary(set.getDouble("salary"));  
127. <mappers>
128.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
129. </mappers><properties resource="jdbc.properties"/>  
130. <mappers>
131.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
132. </mappers><properties resource="jdbc.properties"/>}  
133. <mappers>
134.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
135. </mappers><properties resource="jdbc.properties"/>  
136. <mappers>
137.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
138. </mappers><properties resource="jdbc.properties"/>return (T)monster;  
139. <mappers>
140.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
141. </mappers><properties resource="jdbc.properties"/>  } catch (SQLException e) {  
142. <mappers>
143.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
144. </mappers><properties resource="jdbc.properties"/>  
145. <mappers>
146.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
147. </mappers><properties resource="jdbc.properties"/>throw new RuntimeException(e);  
148. <mappers>
149.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
150. </mappers><properties resource="jdbc.properties"/>  }finally {  
151. <mappers>
152.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
153. </mappers><properties resource="jdbc.properties"/>  
154. <mappers>
155.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
156. </mappers><properties resource="jdbc.properties"/>try {  
157. <mappers>
158.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
159. </mappers><properties resource="jdbc.properties"/>  
160. <mappers>
161.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
162. </mappers><properties resource="jdbc.properties"/><mappers>
163.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
164. </mappers>if (set != null) {  
165. <mappers>
166.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
167. </mappers><properties resource="jdbc.properties"/>  
168. <mappers>
169.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
170. </mappers><properties resource="jdbc.properties"/>  
171. <mappers>
172.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
173. </mappers><properties resource="jdbc.properties"/>  set.close();  
174. <mappers>
175.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
176. </mappers><properties resource="jdbc.properties"/>  
177. <mappers>
178.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
179. </mappers><properties resource="jdbc.properties"/><mappers>
180.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
181. </mappers>}  
182. <mappers>
183.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
184. </mappers><properties resource="jdbc.properties"/>  
185. <mappers>
186.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
187. </mappers><properties resource="jdbc.properties"/><mappers>
188.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
189. </mappers>if (pre != null) {  
190. <mappers>
191.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
192. </mappers><properties resource="jdbc.properties"/>  
193. <mappers>
194.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
195. </mappers><properties resource="jdbc.properties"/>  
196. <mappers>
197.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
198. </mappers><properties resource="jdbc.properties"/>  pre.close();  
199. <mappers>
200.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
201. </mappers><properties resource="jdbc.properties"/>  
202. <mappers>
203.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
204. </mappers><properties resource="jdbc.properties"/><mappers>
205.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
206. </mappers>}  
207. <mappers>
208.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
209. </mappers><properties resource="jdbc.properties"/>  
210. <mappers>
211.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
212. </mappers><properties resource="jdbc.properties"/><mappers>
213.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
214. </mappers>if (connection != null) {  
215. <mappers>
216.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
217. </mappers><properties resource="jdbc.properties"/>  
218. <mappers>
219.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
220. </mappers><properties resource="jdbc.properties"/>  
221. <mappers>
222.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
223. </mappers><properties resource="jdbc.properties"/>  connection.close();  
224. <mappers>
225.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
226. </mappers><properties resource="jdbc.properties"/>  
227. <mappers>
228.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
229. </mappers><properties resource="jdbc.properties"/><mappers>
230.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
231. </mappers>}  
232. <mappers>
233.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
234. </mappers><properties resource="jdbc.properties"/>  
235. <mappers>
236.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
237. </mappers><properties resource="jdbc.properties"/>} catch (Exception e) {  
238. <mappers>
239.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
240. </mappers><properties resource="jdbc.properties"/>  
241. <mappers>
242.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
243. </mappers><properties resource="jdbc.properties"/><mappers>
244.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
245. </mappers>throw new RuntimeException(e);  
246. <mappers>
247.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
248. </mappers><properties resource="jdbc.properties"/>  
249. <mappers>
250.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
251. </mappers><properties resource="jdbc.properties"/>}  
252. <mappers>
253.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
254. </mappers><properties resource="jdbc.properties"/>  }  
255. <mappers>
256.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
257. </mappers><properties resource="jdbc.properties"/>  
258. <mappers>
259.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
260. </mappers><properties resource="jdbc.properties"/>}<mappers>
261.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
262. </mappers>public Connection getConnection(){//Configuration类 返回连接，通过连接对数据库进行操纵  
263. <mappers>
264.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
265. </mappers><properties resource="jdbc.properties"/> return zyConfiguration.build("zy_mybatis.xml");<mappers>
266.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
267. </mappers>}}

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• 必要一个 本身的Configuration类 返回连接，通过连接对数据库进行操纵
  

将Sqlsession封装到实行器

思绪

• 必要写本身的Sqlsession类，它是搭建连接和实行器之间的桥梁，里面封装有 实行器 和 配置文件 以及 操纵DB 的具体方法
  
• 写一个selectOne方法 ，SelectOne() 返回一条记录，一条记录对应一个Monster对象
  

实现

• 必要写本身的Sqlsession类，它是搭建连接和实行器之间的桥梁，里面封装有 实行器 和 配置文件 以及 操纵DB 的具体方法
  

1. public class ZySqlSession {//搭建连接和实行器之间的桥梁<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>//实行器<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>private Executor executor = new ZyExecutor();<mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers>//配置<mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>private ZyConfiguration zyConfiguration = new ZyConfiguration();<mappers>
10.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
11. </mappers>//操纵DB 的具体方法<mappers>
12.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
13. </mappers>//SelectOne 返回一条记录-对象<mappers>
14.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
15. </mappers>public  T selectOne(String statement,Object parameter){  
16. <mappers>
17.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
18. </mappers><properties resource="jdbc.properties"/>  return executor.query(statement,parameter);<mappers>
19.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
20. </mappers>}}

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• 写一个selectOne方法 ，SelectOne() 返回一条记录，一条记录对应一个Monster对象
  

1. //操纵DB 的具体方法<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>//SelectOne 返回一条记录-对象<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>public  T selectOne(String statement,Object parameter){  
6. <mappers>
7.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
8. </mappers><properties resource="jdbc.properties"/>  return executor.query(statement,parameter);<mappers>
9.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
10. </mappers>}

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开发Mapper接口和Mapper.xml

思绪

• 编写MonsterMapper接口，里面有方法getMonsterById（Integer id）根据id返回一个monster对象
  
• 在resources下编写对应的monsterMapper.xml(简化：由于在resources 编译时会在类路径下比较好写)
  
• monsterMapper.xml 编写具体的sql语句，并指定语句类型，id，resultType（和原生Mybatis一样）
  

实现

• 编写MonsterMapper接口，里面有方法getMonsterById（Integer id）根据id返回一个monster对象
  

1. public interface MonsterMapper {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>public Monster getMonsterById(Integer id);}

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• 在resources下编写对应的monsterMapper.xml(简化：由于在resources 编译时会在类路径下比较好写)
  
• monsterMapper.xml 编写具体的sql语句，并指定语句类型，id，resultType（和原生Mybatis一样）
  

1.   
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/><mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>SELECT * FROM monster WHERE id = ?<mappers>
10.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
11. </mappers>

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开发MapperBean，可以和Mapper接口相映射

思绪

• 开发 Function类 ，用于记录对应的Mapper的方法信息，好比sql类型，方法名，实行的sql语句，返回类型，入参类型
  
• 开发 MapperBean类，记录接口信息和接口下的所有方法
  
• Function类 对应 monsterMapper.xml中的信息
  
• MapperBean类 对应 MonsterMapper 接口中的信息
  

实现

• 开发 Function类 ，用于记录对应的Mapper的方法信息，好比sql类型，方法名，实行的sql语句，返回类型，入参类型
  

1. //对应 monsterMapper.xml中的信息public class Function {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>private String sqlType;//sql类型，好比select，insert，update，delete<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>private String funcName;//方法名<mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers>private String sql;//实行的sql语句<mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>private Object resultType;//返回类型<mappers>
10.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
11. </mappers>private String parameterType;//入参类型}

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• 开发 MapperBean类，记录接口信息和接口下的所有方法
  

1. //对应 MonsterMapper 接口中的信息public class MapperBean {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>private String interfaceName;//接口名<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>//<mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers>接口下的所有方法<mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>private List functions;}

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• Function类 对应 monsterMapper.xml中的信息
  
• MapperBean类 对应 MonsterMapper 接口中的信息
  

在Configuration中解析MapperXML获取MapperBean对象

思绪

• 在Configuration 添加方法readMapper(String path)
  
• 通过 path 读取接口对应的Mapper方法
  
• 保存接口下所有的方法信息
  
• 封装成 MapperBean对象
  

实现

• 在Configuration 添加方法readMapper(String path)
  
• 通过 path 读取接口对应的Mapper方法
  
• 保存接口下所有的方法信息
  
• 封装成 MapperBean对象
  

1. //解析MapperXML获取MapperBean对象<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>//path = xml的路径+文件名 是从类的加载路径计算的(如果放在resource目录下 之间传xml文件名即可)<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>public MapperBean readMapper(String path) {  
6. <mappers>
7.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
8. </mappers><properties resource="jdbc.properties"/>  MapperBean mapperBean = new MapperBean();  
9. <mappers>
10.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
11. </mappers><properties resource="jdbc.properties"/>  InputStream resourceAsStream = classLoader.getResourceAsStream(path);  
12. <mappers>
13.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
14. </mappers><properties resource="jdbc.properties"/>  SAXReader reader = new SAXReader();  
15. <mappers>
16.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
17. </mappers><properties resource="jdbc.properties"/>  try {  
18. <mappers>
19.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
20. </mappers><properties resource="jdbc.properties"/>  
21. <mappers>
22.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
23. </mappers><properties resource="jdbc.properties"/>Document document = reader.read(resourceAsStream);  
24. <mappers>
25.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
26. </mappers><properties resource="jdbc.properties"/>  
27. <mappers>
28.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
29. </mappers><properties resource="jdbc.properties"/>Element root = document.getRootElement();  
30. <mappers>
31.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
32. </mappers><properties resource="jdbc.properties"/>  
33. <mappers>
34.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
35. </mappers><properties resource="jdbc.properties"/>String namespace = root.attributeValue("namespace");  
36. <mappers>
37.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
38. </mappers><properties resource="jdbc.properties"/>  
39. <mappers>
40.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
41. </mappers><properties resource="jdbc.properties"/>mapperBean.setInterfaceName(namespace);  
42. <mappers>
43.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
44. </mappers><properties resource="jdbc.properties"/>  
45. <mappers>
46.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
47. </mappers><properties resource="jdbc.properties"/>List list = new ArrayList();//保存接口下所有的方法信息  
48. <mappers>
49.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
50. </mappers><properties resource="jdbc.properties"/>  
51. <mappers>
52.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
53. </mappers><properties resource="jdbc.properties"/>//得到root的迭代器  
54. <mappers>
55.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
56. </mappers><properties resource="jdbc.properties"/>  
57. <mappers>
58.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
59. </mappers><properties resource="jdbc.properties"/>Iterator iterator = root.elementIterator();  
60. <mappers>
61.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
62. </mappers><properties resource="jdbc.properties"/>  
63. <mappers>
64.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
65. </mappers><properties resource="jdbc.properties"/>while(iterator.hasNext()){  
66. <mappers>
67.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
68. </mappers><properties resource="jdbc.properties"/>  
69. <mappers>
70.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
71. </mappers><properties resource="jdbc.properties"/><mappers>
72.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
73. </mappers>Element e = (Element)iterator.next();  
74. <mappers>
75.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
76. </mappers><properties resource="jdbc.properties"/>  
77. <mappers>
78.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
79. </mappers><properties resource="jdbc.properties"/><mappers>
80.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
81. </mappers>String sqlType = e.getName().trim();  
82. <mappers>
83.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
84. </mappers><properties resource="jdbc.properties"/>  
85. <mappers>
86.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
87. </mappers><properties resource="jdbc.properties"/><mappers>
88.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
89. </mappers>String sql = e.getText().trim();  
90. <mappers>
91.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
92. </mappers><properties resource="jdbc.properties"/>  
93. <mappers>
94.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
95. </mappers><properties resource="jdbc.properties"/><mappers>
96.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
97. </mappers>String funcName = e.attributeValue("id");  
98. <mappers>
99.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
100. </mappers><properties resource="jdbc.properties"/>  
101. <mappers>
102.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
103. </mappers><properties resource="jdbc.properties"/><mappers>
104.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
105. </mappers>String resultType = e.attributeValue("resultType");  
106. <mappers>
107.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
108. </mappers><properties resource="jdbc.properties"/>  
109. <mappers>
110.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
111. </mappers><properties resource="jdbc.properties"/><mappers>
112.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
113. </mappers>//ResultType 返回的是一个Object对象 ->反射  
114. <mappers>
115.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
116. </mappers><properties resource="jdbc.properties"/>  
117. <mappers>
118.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
119. </mappers><properties resource="jdbc.properties"/><mappers>
120.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
121. </mappers>Object instance = Class.forName(resultType).newInstance();  
122. <mappers>
123.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
124. </mappers><properties resource="jdbc.properties"/>  
125. <mappers>
126.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
127. </mappers><properties resource="jdbc.properties"/><mappers>
128.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
129. </mappers>//封装 function 对象  
130. <mappers>
131.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
132. </mappers><properties resource="jdbc.properties"/>  
133. <mappers>
134.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
135. </mappers><properties resource="jdbc.properties"/><mappers>
136.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
137. </mappers>Function function = new Function();  
138. <mappers>
139.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
140. </mappers><properties resource="jdbc.properties"/>  
141. <mappers>
142.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
143. </mappers><properties resource="jdbc.properties"/><mappers>
144.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
145. </mappers>function.setSql(sql);  
146. <mappers>
147.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
148. </mappers><properties resource="jdbc.properties"/>  
149. <mappers>
150.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
151. </mappers><properties resource="jdbc.properties"/><mappers>
152.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
153. </mappers>function.setSqlType(sqlType);  
154. <mappers>
155.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
156. </mappers><properties resource="jdbc.properties"/>  
157. <mappers>
158.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
159. </mappers><properties resource="jdbc.properties"/><mappers>
160.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
161. </mappers>function.setFuncName(funcName);  
162. <mappers>
163.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
164. </mappers><properties resource="jdbc.properties"/>  
165. <mappers>
166.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
167. </mappers><properties resource="jdbc.properties"/><mappers>
168.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
169. </mappers>function.setResultType(instance);  
170. <mappers>
171.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
172. </mappers><properties resource="jdbc.properties"/>  
173. <mappers>
174.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
175. </mappers><properties resource="jdbc.properties"/><mappers>
176.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
177. </mappers>//将封装好的function对象 放入 list中  
178. <mappers>
179.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
180. </mappers><properties resource="jdbc.properties"/>  
181. <mappers>
182.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
183. </mappers><properties resource="jdbc.properties"/><mappers>
184.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
185. </mappers>list.add(function);  
186. <mappers>
187.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
188. </mappers><properties resource="jdbc.properties"/>  
189. <mappers>
190.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
191. </mappers><properties resource="jdbc.properties"/><mappers>
192.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
193. </mappers>mapperBean.setFunctions(list);  
194. <mappers>
195.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
196. </mappers><properties resource="jdbc.properties"/>  
197. <mappers>
198.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
199. </mappers><properties resource="jdbc.properties"/>}  
200. <mappers>
201.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
202. </mappers><properties resource="jdbc.properties"/>  } catch (Exception e) {  
203. <mappers>
204.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
205. </mappers><properties resource="jdbc.properties"/>  
206. <mappers>
207.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
208. </mappers><properties resource="jdbc.properties"/>throw new RuntimeException(e);  
209. <mappers>
210.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
211. </mappers><properties resource="jdbc.properties"/>  }  
212. <mappers>
213.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
214. </mappers><properties resource="jdbc.properties"/>  return mapperBean;<mappers>
215.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
216. </mappers>}

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动态代理Mapper方法

思绪

• 在SqlSession中添加方法 getMapper 输入一个Class类型，返回mapper的动态代理对象
  
• 编写动态代理类 实现 InvocationHandler 接口
  
• 取出mapperBean的functions 遍历
  
• 判定 当前要实行的方法和function.getFunctionName是否一致
  
• 调用方法返回 动态代理对象
  
• 编写SqlSessionFactory 会话工厂，可以返回SqlSession
  

实现

• 编写动态代理类 实现 InvocationHandler 接口
  
• 在SqlSession中添加方法 getMapper 输入一个Class类型，返回mapper的动态代理对象
  

1. //返回mapper的动态代理对象<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>public  T getMapper(Class clazz){  
4. <mappers>
5.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
6. </mappers><properties resource="jdbc.properties"/>  return (T) Proxy.newProxyInstance(  
7. <mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers><properties resource="jdbc.properties"/>  
10. <mappers>
11.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
12. </mappers><properties resource="jdbc.properties"/><mappers>
13.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
14. </mappers>clazz.getClassLoader(),  
15. <mappers>
16.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
17. </mappers><properties resource="jdbc.properties"/>  
18. <mappers>
19.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
20. </mappers><properties resource="jdbc.properties"/><mappers>
21.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
22. </mappers>new Class[]{clazz},  
23. <mappers>
24.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
25. </mappers><properties resource="jdbc.properties"/>  
26. <mappers>
27.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
28. </mappers><properties resource="jdbc.properties"/><mappers>
29.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
30. </mappers>new ZyMapperProxy(zyConfiguration,clazz,this));<mappers>
31.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
32. </mappers>}

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• 取出mapperBean的functions 遍历
  
• 判定 当前要实行的方法和function.getFunctionName是否一致
  
• 调用方法返回 动态代理对象
  

1. public class ZyMapperProxy implements InvocationHandler {<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>private ZySqlSession zySqlSession;<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>private String mapperFile;<mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers>private ZyConfiguration zyConfiguration;<mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>public ZyMapperProxy(ZySqlSession zySqlSession, Class clazz, ZyConfiguration zyConfiguration) {  
10. <mappers>
11.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
12. </mappers><properties resource="jdbc.properties"/>  this.zySqlSession = zySqlSession;  
13. <mappers>
14.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
15. </mappers><properties resource="jdbc.properties"/>  this.zyConfiguration = zyConfiguration;  
16. <mappers>
17.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
18. </mappers><properties resource="jdbc.properties"/>  this.mapperFile = clazz.getSimpleName() + ".xml";<mappers>
19.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
20. </mappers>}<mappers>
21.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
22. </mappers>//当实行Mapper接口的代理对象方法时，会实行到invoke方法<mappers>
23.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
24. </mappers>@Override<mappers>
25.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
26. </mappers>public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {  
27. <mappers>
28.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
29. </mappers><properties resource="jdbc.properties"/>  MapperBean mapperBean = zyConfiguration.readMapper(this.mapperFile);  
30. <mappers>
31.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
32. </mappers><properties resource="jdbc.properties"/>  //判定是否为当前xml文件对应的接口  
33. <mappers>
34.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
35. </mappers><properties resource="jdbc.properties"/>  if (!method.getDeclaringClass().getName().equals(mapperBean.getInterfaceName())){  
36. <mappers>
37.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
38. </mappers><properties resource="jdbc.properties"/>  
39. <mappers>
40.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
41. </mappers><properties resource="jdbc.properties"/>return null;  
42. <mappers>
43.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
44. </mappers><properties resource="jdbc.properties"/>  }  
45. <mappers>
46.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
47. </mappers><properties resource="jdbc.properties"/>  //取出mapperBean的functions  
48. <mappers>
49.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
50. </mappers><properties resource="jdbc.properties"/>  List functions = mapperBean.getFunctions();  
51. <mappers>
52.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
53. </mappers><properties resource="jdbc.properties"/>  //判定当前的mapperBean 解析对应的MapperXML后，有方法  
54. <mappers>
55.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
56. </mappers><properties resource="jdbc.properties"/>  if (null != functions || 0 != functions.size()){  
57. <mappers>
58.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
59. </mappers><properties resource="jdbc.properties"/>  
60. <mappers>
61.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
62. </mappers><properties resource="jdbc.properties"/>for (Function function : functions) {  
63. <mappers>
64.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
65. </mappers><properties resource="jdbc.properties"/>  
66. <mappers>
67.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
68. </mappers><properties resource="jdbc.properties"/><mappers>
69.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
70. </mappers>//当前要实行的方法和function.getFunctionName  
71. <mappers>
72.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
73. </mappers><properties resource="jdbc.properties"/>  
74. <mappers>
75.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
76. </mappers><properties resource="jdbc.properties"/><mappers>
77.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
78. </mappers>if (method.getName().equals(function.getFuncName())){  
79. <mappers>
80.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
81. </mappers><properties resource="jdbc.properties"/>  
82. <mappers>
83.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
84. </mappers><properties resource="jdbc.properties"/>  
85. <mappers>
86.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
87. </mappers><properties resource="jdbc.properties"/>  if ("SELECT".equalsIgnoreCase(function.getSqlType())){  
88. <mappers>
89.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
90. </mappers><properties resource="jdbc.properties"/>  
91. <mappers>
92.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
93. </mappers><properties resource="jdbc.properties"/>  
94. <mappers>
95.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
96. </mappers><properties resource="jdbc.properties"/>  
97. <mappers>
98.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
99. </mappers><properties resource="jdbc.properties"/>return zySqlSession.selectOne(function.getSql(),String.valueOf(args[0]));  
100. <mappers>
101.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
102. </mappers><properties resource="jdbc.properties"/>  
103. <mappers>
104.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
105. </mappers><properties resource="jdbc.properties"/>  
106. <mappers>
107.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
108. </mappers><properties resource="jdbc.properties"/>  }  
109. <mappers>
110.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
111. </mappers><properties resource="jdbc.properties"/>  
112. <mappers>
113.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
114. </mappers><properties resource="jdbc.properties"/><mappers>
115.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
116. </mappers>}  
117. <mappers>
118.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
119. </mappers><properties resource="jdbc.properties"/>  
120. <mappers>
121.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
122. </mappers><properties resource="jdbc.properties"/>}  
123. <mappers>
124.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
125. </mappers><properties resource="jdbc.properties"/>  }  
126. <mappers>
127.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
128. </mappers><properties resource="jdbc.properties"/>  return null;<mappers>
129.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
130. </mappers>}}

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• 编写SqlSessionFactory 会话工厂，可以返回SqlSession
  

1. public class ZySqlSessionFactory {  
2. <mappers>
3.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
4. </mappers><properties resource="jdbc.properties"/>  public static ZySqlSession open(){  
5. <mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers><properties resource="jdbc.properties"/>  return new ZySqlSession();<mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>}}

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测试

1. @Testpublic void openSession(){<mappers>
2.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
3. </mappers>ZySqlSession zySqlSession = ZySqlSessionFactory.openSession();<mappers>
4.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
5. </mappers>System.out.println("zySqlSession= "+zySqlSession);<mappers>
6.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
7. </mappers>MonsterMapper mapper = zySqlSession.getMapper(MonsterMapper.class);<mappers>
8.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
9. </mappers>Monster monster = mapper.getMonsterById(1);<mappers>
10.     <mapper resource="com/code_study/mapper/MonsterMapper.xml"/>
11. </mappers>System.out.println("monster= "+monster);}

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