本章节将通过一个完整的实例介绍 <delete> 标签的用法。
（1）MyBatis 配置文件 mybatis-cfg.xml 内容如下：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"https://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<properties resource="database.properties"/>
<environments default="MySqlDatabase" >
<environment id="MySqlDatabase" >
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}"/>
<property name="url" value="${jdbc.url}"/>
<property name="username" value="${jdbc.username}"/>
<property name="password" value="${jdbc.password}"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com/hxstrive/mybatis/delete/demo1/UserMapper.xml" />
</mappers>
</configuration>（2）定义 UserMapper.java 文件，代码如下：
package com.hxstrive.mybatis.delete.demo1;
public interface UserMapper {
/**
* 更新用户信息
* @param userId 用户ID
* @return
*/
int deleteUser(int userId);
}（3）定义 UserMapper.xml 文件，代码如下：
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.hxstrive.mybatis.delete.demo1.UserMapper">
<!-- 使用update实现更新数据的操作，注意：其他属性的用法见insert标签 -->
<delete id="deleteUser" parameterType="int">
DELETE FROM `user` WHERE `user_id`=#{userId, jdbcType=INTEGER}
</delete>
</mapper>上面的 <delete> 标签中定义的 SQL 语句将根据 userId 从 user 表删除用户信息。
（4）客户端代码如下：
package com.hxstrive.mybatis.delete.demo1;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import java.io.InputStream;
public class DeleteDemo1 {
public static void main(String[] args) throws Exception {
// 获取 Mapper 对象
String cfgName = "com/hxstrive/mybatis/delete/demo1/mybatis-cfg.xml";
InputStream input = Resources.getResourceAsStream(cfgName);
SqlSessionFactoryBuilder factoryBuilder = new SqlSessionFactoryBuilder();
SqlSessionFactory sqlFactory = factoryBuilder.build(input);
SqlSession sqlSession = sqlFactory.openSession(true);
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
int result = userMapper.deleteUser(74506);
System.out.println("result=" + result);
}
}
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