mybatis---Mapper动态代理开发

Dear 丶 2022-04-15 21:27 258阅读 0赞

UserMapper接口：

package com.it.mybaties.mapper;
    
    import com.it.mybaties.pojo.User;
    
    public interface UserMapper {
    	
    	public User getUserById(Integer id);
    }

Test:

package com.it.mybaties.junit;
    
    import java.io.InputStream;
    
    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.Test;
    
    
    import com.it.mybaties.mapper.UserMapper;
    import com.it.mybaties.pojo.User;
    
    public class TestMapper {
    	
    	@Test
    	public void fun() throws Exception{
    		String resource = "sqlMapperConfig.xml";
    		InputStream in = Resources.getResourceAsStream(resource);
    		SqlSessionFactory sqlSessionFactory = 
                        new SqlSessionFactoryBuilder().build(in);
    		
    		SqlSession sqlSession = sqlSessionFactory.openSession();
    		
    		UserMapper mapper = sqlSession.getMapper(UserMapper.class);
    		
    		User user = mapper.getUserById(37);
    		System.out.println(user);
    		
    		
    	}
    }

UserMapper.xml:

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "mybatis-3-mapper.dtd" >
    <mapper namespace="com.it.mybaties.mapper.UserMapper">
      <select id="getUserById" resultType="com.it.mybaties.pojo.User" parameterType="Integer">
      	select * from user where id=#{id}
      </select>
      
      <select id="getUserByUsername" parameterType="String" resultType="com.it.mybaties.pojo.User">
      	
      	
      	
      	select * from user where username like "%"#{username}"%"
      </select>
      
      <insert id="insertUser" parameterType="com.it.mybaties.pojo.User">
      	<selectKey keyProperty="id" resultType="Integer" order="AFTER">
      		select LAST_INSERT_ID()
      	</selectKey>
      	insert into user (username,sex,birthday,address) values (#{username},#{sex},#{birthday},#{address})
      </insert>
      
      <update id="updateUser" parameterType="com.it.mybaties.pojo.User">
      	update user set username=#{username},sex=#{sex},birthday=#{birthday},address=#{address}  where id=#{id}
      </update>
      
      <delete id="deleteUser" parameterType="Integer">
      	delete from user where id=#{id}
      </delete>
      
      
    </mapper>

**Mapper接口开发需要遵循以下规范：**

1.  Mapper.xml文件中的namespace与mapper接口的类路径相同。
2.  Mapper接口方法名和Mapper.xml中定义的每个statement的id相同
3.  Mapper接口方法的输入参数类型和mapper.xml中定义的每个sql 的parameterType的类型相同
4.  Mapper接口方法的输出参数类型和mapper.xml中定义的每个sql的resultType的类型相同