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勿忘初心做自己 发表于 2022-9-16 17:23:12

MyBatis快速上手与知识点总结

目录

[*]1、MyBatis概述

[*]1.1MyBatis概述
[*]1.2JDBC缺点
[*]1.3MyBatis优化

[*]2、MyBatis快速入门
[*]3、Mapper代理开发

[*]3.1Mapper代理开发概述
[*]3.2使用Mapper代理要求
[*]3.3案例代码实现

[*]4、核心配置文件

[*]4.1多环境配置
[*]4.2类型别名

[*]5、配置文件实现CRUD

[*]5.1 环境准备
[*]5.2 查询所有数据
[*]5.3 查询
[*]5.4 多条件查询
[*]5.6 添加数据与MyBatis事务
[*]5.7 修改
[*]5.8 删除数据
[*]5.9 MyBatis参数传递

[*]6、通过注解实现CRUD

阅读提示：
本文默认已经预装预装maven
1、MyBatis概述

1.1MyBatis概述

[*]持久层框架，用于简化JDBC开发，是对JDBC的封装
持久层：

[*]负责将数据保存到数据库的代码部分
[*]Java EE三层架构：表现层、业务层、持久层

1.2JDBC缺点

[*]硬编码，不利于维护

[*]注册驱动、获取连接
[*]SQL语句

[*]操作繁琐

[*]手动设置参数
[*]手动封装结果集

1.3MyBatis优化

[*]硬编码 --> 配置文件
[*]繁琐惭怍 --> 框架封装自动完成
2、MyBatis快速入门

[*]需求：查询user表中的所有数据
[*]SQL
create database mybatis;
use mybatis;

drop table if exists tb_user;

create table tb_user(
id int primary key auto_increment,
username varchar(20),
password varchar(20),
gender char(1),
addr varchar(30)
);

INSERT INTO tb_user VALUES (1, 'zhangsan', '123', '男', '北京');
INSERT INTO tb_user VALUES (2, '李四', '234', '女', '天津');
INSERT INTO tb_user VALUES (3, '王五', '11', '男', '西安');
[*]代码实现

[*]创建模块，导入坐标
在pom.xml中配置文件中添加依赖的坐标
注意：需要在项目的resources目录下创建logback的配置文件
<dependencies>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><dependency>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><groupId>org.mybatis</groupId>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><artifactId>mybatis</artifactId>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><version>3.5.5</version>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></dependency>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><dependency>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><groupId>mysql</groupId>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><artifactId>mysql-connector-java</artifactId>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><version>5.1.46</version>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></dependency>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><dependency>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><groupId>junit</groupId>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><artifactId>junit</artifactId>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><version>4.13</version>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><scope>test</scope>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></dependency>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><dependency>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><groupId>org.slf4j</groupId>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><artifactId>slf4j-api</artifactId>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><version>1.7.20</version>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></dependency>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><dependency>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><groupId>ch.qos.logback</groupId>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><artifactId>logback-classic</artifactId>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><version>1.2.3</version>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></dependency>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><dependency>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><groupId>ch.qos.logback</groupId>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><artifactId>logback-core</artifactId>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><version>1.2.3</version>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></dependency>
</dependencies>
[*]编写MyBatis核心文件
核心文件用于替换信息，解决硬编码问题
在模块下的resources目录下创建mybatis的配置文件mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><environments default="development">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><environment id="development">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><transactionManager type="JDBC"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><dataSource type="POOLED">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><property name="driver" value="com.mysql.jdbc.Driver"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><property name="url" value="jdbc:mysql:///mybatis?useSSL=false"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><property name="username" value="root"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><property name="password" value="123456"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></dataSource>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></environment>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></environments>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mapper resource="UserMapper.xml"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></mappers>
</configuration>
[*]编写SQL映射文件
SQL映射文件用于统一管理SQL语句，解决硬编码问题
在模块的resources目录下创建映射配置文件UserMaooer.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="test">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><select id="selectAll" resultType="priv.dandelion.entity.User">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>select * from tb_user;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></select>
</mapper>
[*]编码

[*]实体类
package priv.dandelion.entity;

public class User {

<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>private Integer id;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>private String username;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>private String password;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>private String gender;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>private String address;

<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public User() {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}

<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public User(Integer id, String username, String password, String gender, String address) {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.id = id;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.username = username;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.password = password;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.gender = gender;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.address = address;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}

<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public Integer getId() {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>return id;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}

<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public void setId(Integer id) {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.id = id;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}

<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public String getUsername() {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>return username;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}

<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public void setUsername(String username) {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.username = username;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}

<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public String getPassword() {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>return password;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}

<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public void setPassword(String password) {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.password = password;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}

<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public String getGender() {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>return gender;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}

<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public void setGender(String gender) {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.gender = gender;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}

<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public String getAddress() {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>return address;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}

<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public void setAddress(String address) {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.address = address;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}

<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>@Override
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public String toString() {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>return "User{" +
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>"id=" + id +
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>", username='" + username + '\'' +
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>", password='" + password + '\'' +
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>", gender='" + gender + '\'' +
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>", address='" + address + '\'' +
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>'}';
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}
}
[*]测试类
public static void main(String[] args) throws IOException {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 加载mybatis的核心配置文件，获取SqlSessionFactory
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String resource = "mybatis-config.xml";
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>InputStream inputStream = Resources.getResourceAsStream(resource);
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取Session对象，执行SQL语句
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSession sqlSession = sqlSessionFactory.openSession();
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 执行SQL，处理结果
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>List<User> users = sqlSession.selectList("test.selectAll");
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>System.out.println(users);
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 释放资源
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>sqlSession.close();
}

3、Mapper代理开发

3.1Mapper代理开发概述

解决形如上述测试类中List users = sqlSession.selectList("test.selectAll");的硬编码问题

[*]解决原生方式中的硬编码
[*]简化后期的SQL执行
3.2使用Mapper代理要求

[*]定义与SQL映射文件同名的Mapper接口，并且将Mapper接口和SQL映射文件放置在同一目录下
maven项目开发时要求code和resources分开，可在resources中创建相同包文件来是实现上述效果

[*]设置SQL映射文件的namespace属性未Mapper接口的全限定名
[*]在Mapper接口中定义方法，方法名就是SQL映射文件中SQL语句的id，并且参数类型和返回值类型一致
3.3案例代码实现

[*]修改SQL映射文件UserMapper.xml
同时还要修改其路径
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="priv.dandelion.mapper.UserMapper">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><select id="selectAll" resultType="priv.dandelion.entity.User">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>select * from tb_user;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></select>
</mapper>
[*]创建对应的Mapper接口UserMapper.interface
public interface UserMapper {
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>List<User> selectAll();
}
[*]修改mybatis核心配置文件中加载SQL映射的的路径
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
[*]测试代码
public static void main(String[] args) throws IOException {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 加载mybatis的核心配置文件，获取SqlSessionFactory<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String resource = "mybatis-config.xml";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>InputStream inputStream = Resources.getResourceAsStream(resource);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取Session对象，执行SQL语句<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSession sqlSession = sqlSessionFactory.openSession();<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 执行SQL，处理结果<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取UserMapper接口的代理对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>UserMapper userMapper = sqlSession.getMapper(UserMapper.class);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>List users = userMapper.selectAll();<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>System.out.println(users);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 释放资源<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>sqlSession.close();}
[*]改进
如果Mapper接口名称和SQL映射文件名称相同，并在同一目录下，则可以使用包扫描的方式简化SQL映射文件的加载，简化mybatis核心配置文件
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
4、核心配置文件

4.1多环境配置

在核心配置文件的 environments 标签中其实是可以配置多个 environment ，使用 id 给每段环境起名，在 environments 中使用 default='环境id' 来指定使用哪儿段配置。我们一般就配置一个 environment 即可
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><environments default="development">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><environment id="development">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><transactionManager type="JDBC"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><dataSource type="POOLED">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><property name="driver" value="com.mysql.jdbc.Driver"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><property name="url" value="jdbc:mysql:///mybatis?useSSL=false"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><property name="username" value="root"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><property name="password" value="123456"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></dataSource>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></environment>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></environments>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mapper resource="UserMapper.xml"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></mappers>
</configuration><?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><environments default="development">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><environment id="development">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><transactionManager type="JDBC"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><dataSource type="POOLED">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><property name="driver" value="com.mysql.jdbc.Driver"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><property name="url" value="jdbc:mysql:///mybatis?useSSL=false"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><property name="username" value="root"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><property name="password" value="123456"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></dataSource>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></environment>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></environments>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mapper resource="UserMapper.xml"/>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></mappers>
</configuration>4.2类型别名

映射配置文件中的resultType属性需要配置数据封装的类型（类的全限定名），繁琐
Mybatis 提供了类型别名(typeAliases) 可以简化这部分的书写
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>"http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="test">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><select id="selectAll" resultType="priv.dandelion.entity.User">
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>select * from tb_user;
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers></select>
</mapper>5、配置文件实现CRUD

5.1 环境准备

[*]SQL
-- 删除tb_brand表drop table if exists tb_brand;-- 创建tb_brand表create table tb_brand(<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>-- id 主键<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>id<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers> int primary key auto_increment,<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>-- 品牌名称<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brand_name varchar(20),<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>-- 企业名称<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>company_name varchar(20),<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>-- 排序字段<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>ordered<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>int,<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>-- 描述信息<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>descriptionvarchar(100),<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>-- 状态：0：禁用1：启用<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>status<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers> int);-- 添加数据insert into tb_brand (brand_name, company_name, ordered, description, status)values ('三只松鼠', '三只松鼠股份有限公司', 5, '好吃不上火', 0),<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers> ('华为', '华为技术有限公司', 100, '华为致力于把数字世界带入每个人、每个家庭、每个组织，构建万物互联的智能世界', 1),<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers> ('小米', '小米科技有限公司', 50, 'are you ok', 1);SELECT * FROM tb_brand;
[*]实体类
public class Brand {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>private Integer id;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>private String brand_name;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>private String company_name;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>private Integer ordered;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>private String description;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>private Integer status;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public Brand() {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public Brand(<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>Integer id,<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String brand_name,<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String company_name,<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>Integer ordered,<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String description,<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>Integer status<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>) {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.id = id;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.brand_name = brand_name;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.company_name = company_name;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.ordered = ordered;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.description = description;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.status = status;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public Integer getId() {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>return id;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public void setId(Integer id) {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.id = id;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public String getBrand_name() {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>return brand_name;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public void setBrand_name(String brand_name) {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.brand_name = brand_name;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public String getCompany_name() {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>return company_name;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public void setCompany_name(String company_name) {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.company_name = company_name;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public Integer getOrdered() {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>return ordered;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public void setOrdered(Integer ordered) {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.ordered = ordered;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public String getDescription() {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>return description;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public void setDescription(String description) {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.description = description;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public Integer getStatus() {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>return status;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public void setStatus(Integer status) {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>this.status = status;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>@Override<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public String toString() {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>return "Brand{" +<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>"id=" + id +<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>", brand_name='" + brand_name + '\'' +<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>", company_name='" + company_name + '\'' +<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>", ordered=" + ordered +<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>", description='" + description + '\'' +<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>", status=" + status +<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>'}';<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}}
[*]安装插件MyBatisX
[*]步骤

[*]编写接口方法Mapper接口

[*]参数
[*]返回值

[*]在SQL映射文件中编写SQL语句

[*]MyBatisX插件自动补全
[*]编写SQL
[*]若数据库字段名和实体类字段名不同，则需要解决该问题（见 5.2 SQL映射文件）

[*]编写执行测试

[*]获取SqlSessionFactory
[*]获取sqlSession对象
[*]获取mapper接口的代理对象
[*]执行方法
[*]释放资源

5.2 查询所有数据

本节要点：

[*]测试类的编写方式
[*]解决数据库字段和实体类字段名不同的问题

[*]编写接口方法
public interface BrandMapper {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public List selectAll();}
[*]编写SQL映射文件
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>select *<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>from tb_brand;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>
[*]编写测试方法
@Testpublic void testSelectAll() throws IOException {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取SqlSessionFactory<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String resource = "mybatis-config.xml";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>InputStream inputStream = Resources.getResourceAsStream(resource);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取sqlSession对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSession sqlSession = sqlSessionFactory.openSession();<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取mapper接口的代理对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 执行方法<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>List brands = brandMapper.selectAll();<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>System.out.println(brands);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 释放资源<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>sqlSession.close();}
5.3 查询

本节要点：

[*]MyBatis的SQL映射文件中，SQL语句如何接收对应参数

[*]使用占位符进行参数传递

[*]占位符名称和参数保持一致
[*]占位符

[*]#{占位符名}：会替换为?，防止SQL注入，一般用于替换字段值
[*]${占位符名}：存在SQL注入问题，一般用于执行动态SQL语句，如表名列名不固定的情况（见）

[*]编写接口方法
void update(Brand brand);
[*]SQL映射文件查询代码标签
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>select *<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>from tb_brand where id = #{id};
[*]测试方法
@Test<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public void testSelectByCondition() throws IOException {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 接收参数<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>int status = 1;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String companyName = "华为";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String brandName = "华为";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取SqlSessionFactory<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String resource = "mybatis-config.xml";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>InputStream inputStream = Resources.getResourceAsStream(resource);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSessionFactory sqlSessionFactory =<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers> new SqlSessionFactoryBuilder().build(inputStream);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取sqlSession对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSession sqlSession = sqlSessionFactory.openSession();<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取mapper接口的代理对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 执行方法<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>companyName = "%" + companyName + "%";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brandName = "%" + brandName + "%";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>List brands = brandMapper.selectByCondition(status, companyName, brandName);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>System.out.println(brands);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 释放资源<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>sqlSession.close();<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}
5.4 多条件查询

本节要点：

[*]多条件查询：如果有多个参数，需要使用@Paran("SQL参数占位符名称")注解
[*]多条件的动态条件查询：对象属性名称要和参数占位符名称一致
（详见5-2解决数据库字段和实体类字段名不同的问题）
[*]单条件的动态条件查询：保证key要和参数占位符名称一致

[*]多条件查询

[*]SQL映射文件
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>select *<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>from tb_brand<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>where status = #{status}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>and company_name like #{companyName}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>and brand_name like #{brandName}
[*]散装参数

[*]接口
// 散装参数List selectByCondition(<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>@Param("status")int status,<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers> @Param("companyName")String companyName,<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers> @Param("brandName")String brandName);
[*]测试方法
@Test<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>public void testSelectByCondition() throws IOException {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 接收参数<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>int status = 1;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String companyName = "华为";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String brandName = "华为";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取SqlSessionFactory<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String resource = "mybatis-config.xml";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>InputStream inputStream = Resources.getResourceAsStream(resource);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSessionFactory sqlSessionFactory =<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>new SqlSessionFactoryBuilder().build(inputStream);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取sqlSession对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSession sqlSession = sqlSessionFactory.openSession();<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取mapper接口的代理对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 执行方法<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>companyName = "%" + companyName + "%";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brandName = "%" + brandName + "%";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>List brands = brandMapper.selectByCondition(<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>status, companyName, brandName);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>System.out.println(brands);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 释放资源<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>sqlSession.close();<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>}

[*]对象参数

[*]接口
// 对象参数
List<Brand> selectByCondition(Brand brand);
[*]测试方法
// 细节不表，仅展示执行方法
// 执行方法
Brand brand = new Brand();
brand.setStatus(status);
brand.setCompanyName("%" + companyName + "%");
brand.setBrandName("%" + brandName + "%");
List<Brand> brands = brandMapper.selectByCondition(brand);
System.out.println(brands);

[*]map集合参数

[*]接口
// 集合参数
List<Brand> selectByCondition(Map map);
[*]测试方法
// 细节不表，仅展示执行方法
// 执行方法
Map map = new HashMap();
map.put("status", status);
map.put("companyName", "%" + companyName + "%");
map.put("brandName", "%" + brandName + "%");
List<Brand> brands = brandMapper.selectByCondition(map);
System.out.println(brands);

[*]多条件动态条件查询
优化条件查询，如页面上表单存在多个条件选项，但实际填写表单仅使用部分条件筛选的情况

[*]SQL映射文件
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>select *<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>from tb_brand<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>status = #{status}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>and company_name like #{companyName}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>and brand_name like #{brandName}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>注：

[*]if标签的test属性中可以包含逻辑或等逻辑判断，使用and、or进行连接
[*]若条件SQL中同时包含AND等连接符

[*]对所有的条件前都加AND，并在WHERE后加任意真判断，即WHERE 1=1 AND ... AND ...
[*]加入判断标签造轮子，自行决定添加AND的条件
[*]使用标签替换原SQL中的WHERE关键字，MyBatis将自动进行语法修正，如示例所示

[*]单条件的动态条件查询
优化条件查询：如表单中存在多个条件筛选，但仅有其中一个生效的情况

[*]使用标签

[*]choose标签类似于Java中的switch
[*]when标签类似于Java中的case
[*]otherwise标签类似于Java中的default

[*]SQL映射文件
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>select *<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>from tb_brand<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>status = #{status}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>company_name like #{companyName}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brand_name like #{brandName}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>

5.6 添加数据与MyBatis事务

[*]添加

[*]接口
// 添加
void add(Brand brand);
[*]SQL映射文件
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>insert into tb_brand (brand_name, company_name, ordered, description, status)<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>values (#{brandName}, #{companyName}, #{ordered}, #{description}, #{status});
[*]测试方法
@Testpublic void testAdd() throws IOException {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 接收参数<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>int status = 1;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String companyName = "aaa";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String brandName = "xxx";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String description = "这是一段介绍";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>int ordered = 100;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取SqlSessionFactory<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String resource = "mybatis-config.xml";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>InputStream inputStream = Resources.getResourceAsStream(resource);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSessionFactory sqlSessionFactory =<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers> new SqlSessionFactoryBuilder().build(inputStream);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取sqlSession对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// SqlSession sqlSession = sqlSessionFactory.openSession();<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSession sqlSession = sqlSessionFactory.openSession(true);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取mapper接口的代理对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 执行方法<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>Brand brand = new Brand();<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brand.setStatus(1);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brand.setBrandName(brandName);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brand.setCompanyName(companyName);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brand.setDescription(description);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brand.setOrdered(ordered);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brandMapper.add(brand);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>System.out.println("添加成功");<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 提交事务<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// sqlSession.commit();<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 释放资源<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>sqlSession.close();}

[*]Mybatis事务
MyBatis默认手动事务，执行添加等操作时会自动回滚

[*]MyBayis事务处理的方法
// 方法一：在获取sqlSession对象时设置参数，开启自动事务
SqlSession sqlSession = sqlSessionFactory.openSession(true);
sqlSession.close();
// 方法二：手动提交事务
SqlSession sqlSession = sqlSessionFactory.openSession();
sqlSession.commit();
sqlSession.close();

[*]添加 - 主键返回
传入实体类对象进行数据添加，在数据添加完成后，会将id信息写回该实体类对象

[*]SQL映射文件
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>insert into tb_brand (brand_name, company_name, ordered, description, status)<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>values (#{brandName}, #{companyName}, #{ordered}, #{description}, #{status});
[*]获取写回信息
Integer id = brand.getId();

5.7 修改

[*]修改整条数据

[*]接口
// 修改，可使用int返回值，返回受影响行数
void update(Brand brand);
[*]SQL映射文件
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>update tb_brand<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>set brand_name = #{brandName},<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>set company_name = #{companyName},<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>set ordered = #{ordered},<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>set description = #{description},<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>set status = #{status}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>where id = #{id};

[*]修改部分字段
优化上述代码应对仅修改部分属性导致其他属性数据丢失问题
使用标签替换set关键字列表，区别于标签，注意语法

[*]SQL映射文件
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>update tb_brand<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brand_name = #{brandName},<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>company_name = #{companyName},<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>ordered = #{ordered},<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>description = #{description},<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>status = #{status},<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>where id = #{id};
[*]测试代码
@Testpublic void testUpdate() throws IOException {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 接收参数<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>int id = 5;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>int status = 0;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String companyName = "AAA";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String brandName = "XXX";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>int ordered = 300;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取SqlSessionFactory<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String resource = "mybatis-config.xml";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>InputStream inputStream = Resources.getResourceAsStream(resource);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSessionFactory sqlSessionFactory =<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers> new SqlSessionFactoryBuilder().build(inputStream);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取sqlSession对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSession sqlSession = sqlSessionFactory.openSession(true);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取mapper接口的代理对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 执行方法<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>Brand brand = new Brand();<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brand.setId(id);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brand.setStatus(status);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brand.setBrandName(brandName);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brand.setCompanyName(companyName);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brand.setOrdered(ordered);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brandMapper.update(brand);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>System.out.println("修改成功");<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 释放资源<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>sqlSession.close();}

5.8 删除数据

[*]删除一条数据

[*]接口
// 删除一条数据
void deleteById(int id);
[*]SQL映射文件
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>delete<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>from tb_brand<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>where id = #{id};
[*]测试
@Testpublic void testDeleteById() throws IOException {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 接收参数<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>int id = 5;<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取SqlSessionFactory<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String resource = "mybatis-config.xml";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>InputStream inputStream = Resources.getResourceAsStream(resource);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSessionFactory sqlSessionFactory =<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers> new SqlSessionFactoryBuilder().build(inputStream);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取sqlSession对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSession sqlSession = sqlSessionFactory.openSession(true);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取mapper接口的代理对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 执行方法<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brandMapper.deleteById(id);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>System.out.println("删除成功");<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 释放资源<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>sqlSession.close();}

[*]批量删除数据
用于解决删除时传入参数为数组的情况

[*]使用标签代替SQL语句中的id in (?, ?, ..., ?)

[*]collection属性为MyBatis封装后数组对应的key，封装后属性值应为array（见注释）

[*]MyBatis默认会将数组参数封装为Map集合，其key为array，即 array = ids
[*]可在接口中对参数数组使用@Param注解，将封装后的key手动命名，则可在映射文件中使用

[*]separator属性为分隔符
[*]open和close属性分别为在前后拼接字符，主要用于代码规范，示例中未展示

[*]接口
// 删除多个数据
void deleteByIds(@Param("ids")int[] ids);
[*]SQL映射文件
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>delete<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>from tb_brand<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>where id<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>in (<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>#{id}<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>);
[*]测试
@Testpublic void testDeleteByIds() throws IOException {<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 接收参数<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>int[] ids = {6, 7};<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取SqlSessionFactory<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>String resource = "mybatis-config.xml";<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>InputStream inputStream = Resources.getResourceAsStream(resource);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSessionFactory sqlSessionFactory =<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers> new SqlSessionFactoryBuilder().build(inputStream);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取sqlSession对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>SqlSession sqlSession = sqlSessionFactory.openSession(true);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 获取mapper接口的代理对象<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 执行方法<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>brandMapper.deleteByIds(ids);<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>System.out.println("删除成功");<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>// 释放资源<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>sqlSession.close();}

5.9 MyBatis参数传递

[*]概述
[*]多个参数
设有如下代码：
User select(@Param("username") String username,@Param("password") String password);MyBatis会将散装的多个参数封装为Map集合

[*]若不使用@Param注解，则会使用以下命名规则：
map.put("arg0"，参数值1);
map.put("arg1"，参数值2);
map.put("param1"，参数值1);
map.put("param2"，参数值2);即Map集合中的参数的key分别为arg0, arg1, param1, param2
[*]使用@Param注解会将Map集合中的参数的arg替换为指定内容，增强其可读性

[*]单个参数

[*]POJO类型：直接使用，要求属性名和参数占位符名称一致（见 5.2 SQL映射文件）
[*]Map集合类型：直接使用，要求key和参数占位符名称一致（见 5.2 SQL映射文件）
[*]Collection集合类型：封装Map集合，可以使用@Param注解替换Map集合中默认arg键名
map.put("arg0"，collection集合);
map.put("collection"，collection集合;
[*]List集合类型：封装为Map集合，可以使用@Param注解，替换Map集合中默认的arg键名
map.put("arg0"，list集合);
map.put("collection"，list集合);
map.put("list"，list集合);
[*]Array类型：封装为Map集合，可以使用@Param注解，替换Map集合中默认的arg键名
map.put("arg0"，数组);
map.put("array"，数组);
[*]其他类型：直接使用，与参数占位符无关，但尽量见名知意

6、通过注解实现CRUD

[*]概述

[*]用于简化开发，可以对简单的查询使用注解进行操作，以替换xml中的statement
[*]对于复杂的查询，仍然建议使用xml配置文件，否则代码会十分混乱

[*]使用方法

[*]注解（部分）

[*]查询：@Select
[*]添加：@Insert
[*]修改：@Update
[*]删除：@Delete

[*]示例

[*]使用注解简化查询

[*]原接口
Brand selectById(int id);
[*]原SQL映射文件
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>select *<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>from tb_brand<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>where id = #{id};

[*]使用注解进行开发

[*]接口
@ResultMap("brandResultMap") // 解决数据库和实体类字段名称不同
@Select("select * from tb_brand where id = #{id}") // 查询语句
Brand selectById(int id);
[*]SQL映射文件：不再需要原先的statement
<mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers><mappers>
<mapper resource="priv/dandelion/mapper/UserMapper.xml"/>
</mappers>

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