mapper代理开发

主配置文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
  PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
  "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
  <environments default="development">
    <environment id="development">
      <transactionManager type="JDBC"/>
      <dataSource type="POOLED">
        <property name="driver" value="com.mysql.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/MyBatis?useUnicode=true&characterEncoding=UTF8"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
      </dataSource>
    </environment>
  </environments>
  <!-- 加载映射文件 -->
  <mappers>
    <mapper resource="mapper/usermapper.xml"/>
  </mappers>
</configuration>

映射文件

<!DOCTYPE mapper
    PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
    "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- 对sql进行分开处理，隔离 -->
<mapper namespace="com.hl.mybatis.first.mapper.UserMapper">
    <!-- 执行数据库的查询 ID用来标识次sql语句，称为Statement的ID  
        #{}表示一个占位符
        parameterType指定输入参数类型
        id:接收参数名叫id,如果参数为简单类型，参数名随意
        resultType:输出结果的类型,单条记录所映射的对象类。
    -->
    <select id="findUserById" parameterType="int" resultType="com.hl.myabtis.first.beas.User">
        select * FROM user WHERE id = #{id}
    </select>
    <!--${value}表示sql拼接串  -->
    <select id="findUserByNaem" parameterType="String" resultType="com.hl.myabtis.first.beas.User">
        select * FROM user WHERE address LIKE '%${value}%'
    </select>

    <!-- 添加用户 
        SELECT_LAST_INSERT_ID()只适用于自增长情况
        keyProperty:将查询到的结果设置到parameterType指定的属性
        order：执行顺序，在插入后执行
        resultType：结果类型
    -->
    <insert id="insertUser" parameterType="com.hl.myabtis.first.beas.User">
        <selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer">
        SELECT LAST_INSERT_ID()
    </selectKey>
        insert into user (username,birthday,sex,address) value(#{username},#{birthday},#{sex},#{address})
    </insert>
    <!-- 删除 
        parameterType:参数类型
    -->
    <delete id="deleteUser" parameterType="java.lang.Integer">
        delete from user where id = #{value}
    </delete>
    <!-- 更新
        需求：根据ID更新用户信息
        parameterType:需要更新的用户信息
        #{id}：从输入的user对象中获取ID属性，名称需要和属性名一致
     -->
     <update id="updateUserByID" parameterType="com.hl.myabtis.first.beas.User">
        update user set username = #{username},birthday = #{birthday},sex = #{sex},address = #{address} where id = #{id}
     </update>
</mapper>

mapper接口

package com.hl.mybatis.first.mapper;


import java.util.List;

import com.hl.myabtis.first.beas.User;

public interface UserMapper {

    //根据id查询用户信息
    public User findUserById(int id) throws Exception;
    //添加用户信息
    public void insertUser(User user);
    //根据id删除用户
    public void deleteUser(int id);
    //根据用户姓名模糊查找
    public List<User> findUserByName(String name);
}

测试：

package com.hl.mybatis.first.test;

import java.io.InputStream;
import java.util.List;

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 org.junit.Before;
import org.junit.Test;

import com.hl.myabtis.first.beas.User;
import com.hl.mybatis.first.mapper.UserMapper;

public class UserMapperTest {

    private SqlSessionFactory sqlSessionFactory;

    @Before
    public void before() throws Exception{
        //创建sqlSessionFactory
        //创建会话工厂
        String resource = "SqlMapConfig.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource );
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    }
    @Test
    public void testInsertUser(){
        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper usermapper = sqlSession.getMapper(UserMapper.class);
        User user = new User();
        user.setUsername("卫庄");
        user.setAddress("秦时明月之君临天下");
        user.setSex('1');
        usermapper.insertUser(user);
    }
    @Test
    public void testfindUserByID() throws Exception{
        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper usermapper = sqlSession.getMapper(UserMapper.class);
        User user = usermapper.findUserById(3);
        System.out.println(user);
        sqlSession.commit();
        sqlSession.close();
    }
    @Test
    public void testDeleteUserByID() throws Exception{
        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper usermapper = sqlSession.getMapper(UserMapper.class);
        usermapper.deleteUser(14);
        sqlSession.close();
    }
    @Test
    public void testfindUserByName() throws Exception{
        SqlSession sqlSession = sqlSessionFactory.openSession();
        UserMapper usermapper = sqlSession.getMapper(UserMapper.class);
        List<User> userList = usermapper.findUserByName("秦时明月");
        sqlSession.close();
        for (User user : userList) {
            System.out.println(user);
        }
    }
}

mapper代理开发规范参考​