最近正在集成SpringBoot与MyBatis-plus,体验感很好啊

sql

1. CREATE TABLE `class` (
2.   `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '编号',
3.   `name` varchar(30) DEFAULT NULL COMMENT '班级名',
4.   `floor` int(3) DEFAULT NULL COMMENT '楼层',
5.   `teacher_id` int(11) DEFAULT NULL COMMENT '老师编号(FK)',
6.   PRIMARY KEY (`id`)
7. ) ENGINE=InnoDB AUTO_INCREMENT=30 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci COMMENT='班级信息表';
8. INSERT INTO `class` VALUES ('1', '1年级2班', '4', '2');
9. INSERT INTO `class` VALUES ('2', '1年级3班', '4', '2');
10. INSERT INTO `class` VALUES ('3', '2年级1班', '1', '4');
11. INSERT INTO `class` VALUES ('4', '2年级2班', '2', '5');
12. INSERT INTO `class` VALUES ('5', '2年级3班', '3', '6');
13. INSERT INTO `class` VALUES ('6', '3年级1班', '4', '7');
14. INSERT INTO `class` VALUES ('7', '3年级2班', '1', '8');
15. INSERT INTO `class` VALUES ('8', '3年级3班', '2', '9');
16. INSERT INTO `class` VALUES ('9', '4年级1班', '3', '10');
17. INSERT INTO `class` VALUES ('10', '4年级2班', '4', '11');
18. INSERT INTO `class` VALUES ('11', '4年级3班', '1', '12');
19. INSERT INTO `class` VALUES ('12', '5年级1班', '2', '13');
20. INSERT INTO `class` VALUES ('13', '5年级3班', '4', '15');
21. INSERT INTO `class` VALUES ('14', '6年级2班', '2', '17');
22. INSERT INTO `class` VALUES ('15', '6年级3班', '3', '18');
23. INSERT INTO `class` VALUES ('16', '1年级4班', '4', '99');
24. INSERT INTO `class` VALUES ('17', '2年级4班', '2', '99');
25. INSERT INTO `class` VALUES ('18', '3年级4班', '1', '99');
26. INSERT INTO `class` VALUES ('19', '4年级1班', '1', '20');
27. INSERT INTO `class` VALUES ('30', '4年级1班', '22', '20');
29. CREATE TABLE `teacher` (
30.   `id` int(11) NOT NULL AUTO_INCREMENT COMMENT '编号',
31.   `name` varchar(30) DEFAULT NULL COMMENT '名字',
32.   `age` int(2) DEFAULT NULL COMMENT '年龄',
33.   `title` varchar(30) DEFAULT NULL COMMENT '职称',
34.   `manager` int(11) DEFAULT NULL COMMENT '上司编号(FK)',
35.   `salary` int(6) DEFAULT NULL COMMENT '工资',
36.   `comm` int(6) DEFAULT NULL COMMENT '奖金',
37.   `gender` char(1) DEFAULT NULL COMMENT '性别',
38.   `subject_id` int(11) DEFAULT NULL COMMENT '科目编号(FK)',
39.   PRIMARY KEY (`id`)
40. ) ENGINE=InnoDB AUTO_INCREMENT=21 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_general_ci COMMENT='老师信息表';
41. INSERT INTO `teacher` VALUES ('1', '刘苍松', '55', '总监', '20', '10000', '5000', '男', '1');
42. INSERT INTO `teacher` VALUES ('2', '范传奇', '33', '三级讲师', '1', '3000', null, '男', '2');
43. INSERT INTO `teacher` VALUES ('3', '王克晶', '32', '一级讲师', '1', '8000', '3000', '女', '3');
44. INSERT INTO `teacher` VALUES ('4', '刘国斌', '29', '二级讲师', '1', '7300', '3400', '男', '4');
45. INSERT INTO `teacher` VALUES ('5', '成恒', '35', '三级讲师', '1', '5200', '4600', '男', '5');
46. INSERT INTO `teacher` VALUES ('6', '张皓岚', '33', '二级讲师', '1', '7800', '700', '男', '2');
47. INSERT INTO `teacher` VALUES ('7', '胡悦', '25', '一级讲师', '1', '9000', '2800', '女', '1');
48. INSERT INTO `teacher` VALUES ('8', '齐雷', '45', '总监', '20', '9800', '7800', '男', '3');
49. INSERT INTO `teacher` VALUES ('9', '王海涛', '44', '二级讲师', '8', '3100', '1200', '男', '4');
50. INSERT INTO `teacher` VALUES ('10', '张久军', '39', '一级讲师', '8', '2000', '6000', '男', '5');
51. INSERT INTO `teacher` VALUES ('11', '于健', '27', '二级讲师', '12', '3800', null, '男', '2');
52. INSERT INTO `teacher` VALUES ('12', '张立志', '34', '总监', '20', '13000', '900', '男', '3');
53. INSERT INTO `teacher` VALUES ('13', '吴华', '46', '总监', '20', '8700', '6900', '男', '5');
54. INSERT INTO `teacher` VALUES ('14', '李大帅', '29', '三级讲师', '13', '7000', null, '男', '1');
55. INSERT INTO `teacher` VALUES ('15', '田浩', '26', '二级讲师', '13', '5600', '1900', '男', '4');
56. INSERT INTO `teacher` VALUES ('16', '肖旭伟', '36', '一级讲师', '12', '6800', '600', '男', '2');
57. INSERT INTO `teacher` VALUES ('17', '张敏', '29', '三级讲师', '13', '6100', '400', '女', '3');
58. INSERT INTO `teacher` VALUES ('18', '赵微', '26', '二级讲师', '13', '4600', '6500', '女', '4');
59. INSERT INTO `teacher` VALUES ('19', '李源', '25', '三级讲师', '13', '6300', '0', '男', '4');
60. INSERT INTO `teacher` VALUES ('20', '韩少云', '55', '老板', null, '1', '0', '男', null);

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pom.xml

1.         <dependency>
2.             <groupId>mysql</groupId>
3.             <artifactId>mysql-connector-java</artifactId>
4.             <version>8.0.28</version>
5.         </dependency>
6.                 <dependency>
7.             <groupId>com.alibaba</groupId>
8.             <artifactId>druid</artifactId>
9.             <version>1.2.8</version>
10.         </dependency>
11.                 <dependency>
12.             <groupId>org.projectlombok</groupId>
13.             <artifactId>lombok</artifactId>
14.             <version>1.18.24</version>
15.         </dependency>
16.                 <dependency>
17.             <groupId>com.baomidou</groupId>
18.             <artifactId>mybatis-plus-boot-starter</artifactId>
19.             <version>3.5.3</version>
20.         </dependency>

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application.yml

1. spring:
2.   # 数据库连接配置
3.   datasource:
4.     driver-class-name: com.mysql.cj.jdbc.Driver
5.     type: com.alibaba.druid.pool.DruidDataSource
6.     url: jdbc:mysql://localhost:3306/hedu?useSSL=false&serverTimeZone=Asia/Shanghai
7.     username: root
8.     password: root
9. # mybatis-plus配置
10. mybatis-plus:
11.   mapper-locations: classpath:mappers/*.xml
12.   configuration:
13.     log-impl: org.apache.ibatis.logging.stdout.StdOutImpl

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Mybatis-plus的分页插件的配置

1. package cn.highedu.boot.config;
3. import com.baomidou.mybatisplus.annotation.DbType;
4. import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
5. import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
6. import org.springframework.context.annotation.Bean;
7. import org.springframework.context.annotation.Configuration;
10. @Configuration
11. public class MybatisPlusConfig {
12.     /**
13.      * 分页插件的配置
14.      * @return
15.      */
16.     @Bean
17.     public MybatisPlusInterceptor paginationInterceptor(){
18.         MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
19.         /**
20.          * DbType.XXX
21.          * XXX 为具体的数据库类型如MYSQL,ORACLE
22.          */
23.         interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
24.         return interceptor;
25.     }
26. }

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创建基本类

Class

1. package cn.highedu.boot.entity;
3. import com.baomidou.mybatisplus.annotation.IdType;
4. import com.baomidou.mybatisplus.annotation.TableId;
5. import lombok.AllArgsConstructor;
6. import lombok.Data;
7. import lombok.NoArgsConstructor;
9. @Data
10. @AllArgsConstructor
11. @NoArgsConstructor
12. public class Class {
13.     @TableId(type = IdType.AUTO)
14.     private Integer id;
15.     private String name;
16.     private Integer floor;
17.     private Integer teacherId;
18. }

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ClassMapper

1. package cn.highedu.boot.mapper;
3. import cn.highedu.boot.entity.Class;
4. import com.baomidou.mybatisplus.core.mapper.BaseMapper;
5. import org.apache.ibatis.annotations.*;
7. @Mapper
8. public interface ClassMapper extends BaseMapper<Class> {
9. }

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ClassService

1. package cn.highedu.boot.service;
3. import cn.highedu.boot.entity.Class;
4. import com.baomidou.mybatisplus.extension.service.IService;
6. public interface ClassService extends IService<Class> {
7. }

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ClassServiceImpl

1. package cn.highedu.boot.service.impl;
3. import cn.highedu.boot.entity.Class;
4. import cn.highedu.boot.mapper.ClassMapper;
5. import cn.highedu.boot.service.ClassService;
6. import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
7. import org.springframework.stereotype.Service;
9. @Service
10. public class ClassServiceImpl extends ServiceImpl<ClassMapper, Class> implements ClassService {
11. }

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teacher

1. package cn.highedu.boot.entity;
3. import lombok.AllArgsConstructor;
4. import lombok.Data;
5. import lombok.NoArgsConstructor;
7. @Data
8. @AllArgsConstructor
9. @NoArgsConstructor
10. public class Teacher {
11.     private Integer id;
12.     private String name;
13.     private Integer age;
14.     private String title;
15.     private Integer manager;
16.     private Integer salary;
17.     private Integer comm;
18.     private Character gender;
19.     private Integer subjectId;
20. }

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TeacherMapper

1. package cn.highedu.boot.mapper;
3. import cn.highedu.boot.entity.Teacher;
4. import com.baomidou.mybatisplus.core.mapper.BaseMapper;
5. import org.apache.ibatis.annotations.*;
7. @Mapper
8. public interface TeacherMapper extends BaseMapper<Teacher> {
9. }

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TeacherService

1. package cn.highedu.boot.service;
3. import cn.highedu.boot.entity.Teacher;
4. import com.baomidou.mybatisplus.extension.service.IService;
6. public interface TeacherService extends IService<Teacher> {
7. }

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TeacherServiceImpl

1. package cn.highedu.boot.service.impl;
3. import cn.highedu.boot.entity.Teacher;
4. import cn.highedu.boot.mapper.TeacherMapper;
5. import cn.highedu.boot.service.TeacherService;
6. import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
7. import org.springframework.stereotype.Service;
9. @Service
10. public class TeacherServiceImpl extends ServiceImpl<TeacherMapper, Teacher> implements TeacherService {
11. }

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单表操作

SingleTableOperationTest

1. package cn.highedu.boot.service;
3. import cn.highedu.boot.entity.Class;
4. import cn.highedu.boot.mapper.ClassMapper;
5. import cn.highedu.boot.service.impl.ClassServiceImpl;
6. import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
7. import com.baomidou.mybatisplus.core.toolkit.Wrappers;
8. import org.junit.jupiter.api.Test;
9. import org.springframework.beans.factory.annotation.Autowired;
10. import org.springframework.boot.test.context.SpringBootTest;
12. import java.util.List;
14. @SpringBootTest
15. class ClassServiceTest  extends ClassServiceImpl {
17.     @Autowired
18.     private ClassMapper classMapperSimple;
20.     //基本操作
21.     //insert
22.     /**
23.      * 新增一条记录
24.      */
25.     @Test
26.     void simpleAddOne(){
27.         Class addOneClazz = new Class();
28.         addOneClazz.setName("4年级1班");
29.         addOneClazz.setFloor(22);
30.         addOneClazz.setTeacherId(20);
31.         //INSERT INTO class ( name, floor, teacher_id ) VALUES ( ?, ?, ? )
32.         int addOneResult = classMapperSimple.insert(addOneClazz);
33.         System.out.println(addOneResult);
34.     }
36.     //delete
37.     /**
38.      * 根据Id删除一条记录
39.      */
40.     @Test
41.     void simpleDeleteOneById(){
42.         //DELETE FROM class WHERE id=?
43.         int deleteByIdResult = classMapperSimple.deleteById(1);
44.         System.out.println(deleteByIdResult);
45.     }
47.     //update
48.     /**
49.      * 根据Id更改一条记录
50.      */
51.     @Test
52.     void simpleUpdateOneById(){
53.         Class updateClass = new Class();
54.         updateClass.setId(2);
55.         updateClass.setName("1年级3班");
56.         updateClass.setFloor(4);
57.         updateClass.setTeacherId(2);
58.         //UPDATE class SET name=?, floor=?, teacher_id=? WHERE id=?
59.         int updateByIdResult = classMapperSimple.updateById(updateClass);
60.         System.out.println(updateByIdResult);
61.     }
63.     //select
64.     /**
65.      * 根据Id查询一条记录
66.      */
67.     @Test
68.     void simpleQueryOneById(){
69.         //SELECT id,name,floor,teacher_id FROM class WHERE id=?
70.         Class queryOneClass = classMapperSimple.selectById(1);
71.         System.out.println(queryOneClass);
72.     }
74.     /**
75.      * 查询所有记录
76.      */
77.     @Test
78.     void simpleQueryAll() {
79.         //SELECT id,name,floor,teacher_id FROM class
80.         List<Class> queryClasses = classMapperSimple.selectList(null);
81.         System.out.println(queryClasses);
82.     }
85.     /**
86.      *|     函数名   |     说明     |
87.      *| ----------- | ----------- |
88.      *|      eq     |     等于     |
89.      *|      ne     |     不等     |
90.      *|      gt     |     大于     |
91.      *|      it     |     小于     |
92.      *|    between  | 在值1到值2之间 |
93.      *|     like    |   模糊查询    |
94.      *|     isNull  |  字段为NULL   |
95.      */
97.     @Autowired
98.     private ClassMapper classMapperComplex;
100.     //进阶操作
102.     //单表操作
103.     //select
104.     /**
105.      * 根据Id查询条数据
106.      */
107.     @Test
108.     void complexQueryOne(){
109.         LambdaQueryWrapper<Class> queryWrapper = Wrappers.lambdaQuery();
110.         queryWrapper.eq(Class::getId, 1);
111.         //SELECT id,name,floor,teacher_id FROM class WHERE (id = ?);
112.         Class complexQueryOne = classMapperComplex.selectOne(queryWrapper);
113.         System.out.println(complexQueryOne);
114.     }
115.     /**
116.      * 查询相同条件的数据
117.      */
118.     @Test
119.     void complexQueryAll(){
120.         LambdaQueryWrapper<Class> queryWrapper = Wrappers.lambdaQuery();
121.         queryWrapper.eq(Class::getFloor,1);
122.         //SELECT id,name,floor,teacher_id FROM class WHERE (floor = ?);
123.         List<Class> complexQueryAll = classMapperComplex.selectList(queryWrapper);
124.         System.out.println(complexQueryAll);
125.     }
127.     /**
128.      * 查询范围内的数据
129.      */
130.     @Test
131.     void complexBetweenQuery(){
132.         LambdaQueryWrapper<Class> queryWrapper = Wrappers.lambdaQuery();
133.         queryWrapper.between(Class::getFloor,1,3);
134.         //SELECT id,name,floor,teacher_id FROM class WHERE (floor BETWEEN ? AND ?);
135.         List<Class> complexQueryAll = classMapperComplex.selectList(queryWrapper);
136.         System.out.println(complexQueryAll);
137.     }
139.     /**
140.      * 模糊查询
141.      * like():前后加百分号,如 %1年级%
142.      * likeLeft():前面加百分号,如 %1年级
143.      * likeRight():后面加百分号,如 1年级%
144.      */
145.     @Test
146.     void complexLikeQuery(){
147.         LambdaQueryWrapper<Class> queryWrapper = Wrappers.lambdaQuery();
148.         queryWrapper.likeRight(Class::getName,"1年级");
149.         // SELECT id,name,floor,teacher_id FROM class WHERE (name LIKE ?);
150.         List<Class> complexLikeQuery = classMapperComplex.selectList(queryWrapper);
151.         System.out.println(complexLikeQuery);
152.     }
154.     /**
155.      * 按照楼层升序排列,从小到大
156.      */
157.     @Test
158.     void complexOrderQuery(){
159.         LambdaQueryWrapper<Class> queryWrapper = Wrappers.lambdaQuery();
160.         //condition ：条件，返回boolean，当condition为true，进行排序，如果为false，则不排序
161.         //isAsc：是否为升序，true为升序，false为降序
162.         //columns：需要操作的列
163.         queryWrapper.orderBy(true,true,Class::getFloor);
164.         List<Class> complexOrderByAscQuery= classMapperComplex.selectList(queryWrapper);
165.         System.out.println(complexOrderByAscQuery);
166.     }
167.     /**
168.      * 分页查询
169.      */
170.     @Test
171.     void complexPageQuery(){
172.         Page<Class> page = new Page<>(1,3);
173.         classMapperComplex.selectPage(page, null);
174.         System.out.println(page.getRecords());//每页数据list集合
177.         System.out.println(page.getCurrent());//当前页
178.         System.out.println(page.getSize());//每页显示记录数
179.         System.out.println(page.getTotal());//总记录数
180.         System.out.println(page.getPages());//总页数
182.         System.out.println(page.hasPrevious());//上一页
183.         System.out.println(page.hasNext());//下一页
184.     }
185. }

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多表操作

MultipleTableOperationTest

[code][/code]
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