(一)相應的規則
Mapper動態代理需要創建Mapeer接口和與其相對應的XML文件。
一般我們可以先創建好xml文件,因爲:
1、 Mapper.xml文件中的namespace與mapper接口的類路徑相同。
2、 Mapper接口方法名和Mapper.xml中定義的每個statement的id相同
3、 Mapper接口方法的輸入參數類型和mapper.xml中定義的每個sql 的parameterType的類型相同
4、 Mapper接口方法的輸出參數類型和mapper.xml中定義的每個sql的resultType的類型相同
工程文件目錄:
(二)Mapper.xml(UserMapper.xml)
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.ydalien.mapper.UserMapper">
<!-- 根據id獲取用戶信息 -->
<!-- parameterType:表示輸入類型
resultType:表示輸出類型,這裏是自定義的POJO類型
-->
<select id="findUserById" parameterType="int" resultType="com.ydalien.po.User">
select * from user where id = #{id}
</select>
<!-- 自定義條件查詢用戶列表 -->
<select id="findUserByUsername" parameterType="java.lang.String" resultType="com.ydalien.po.User">
select * from user where username like '%${value}%'
</select>
<!-- 添加用戶 -->
<insert id="insertUser" parameterType="com.ydalien.po.User">
<selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer">
select LAST_INSERT_ID()
</selectKey>
insert into user(username,sex,address)
values(#{username},#{sex},#{address})
</insert>
<!-- 刪除用戶 -->
<delete id="deleteUserById" parameterType="int">
delete from user where id=#{id}
</delete>
<!-- 更新用戶 -->
<update id="updateUser" parameterType="com.ydalien.po.User">
update user set username=#{username},sex=#{sex},address=#{address}
where id=#{id}
</update>
</mapper>
(三)mapper接口(UserMapper.java)
package com.ydalien.mapper;
import com.ydalien.po.User;
public interface UserMapper {
//通過id查用戶
public User findUserById(int id) throws Exception;
//插入用戶
public void insertUser(User user) throws Exception;
}
(四)將mapper加入全局配置文件(SqlMapConfig.xml)
<!-- 加載映射文件 -->
<mappers>
<mapper resource="com/ydalien/mapper/UserMapper.xml"/>
</mappers>
(五)測試類(UserMapperTest.java)
package com.ydalien.test;
import static org.junit.Assert.*;
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.Before;
import org.junit.Test;
import com.ydalien.mapper.UserMapper;
import com.ydalien.po.User;
public class UserMapperTest {
private SqlSessionFactory sqlSessionFactory;
@Before
public void setUp() throws Exception {
String resource = "sqlMapConfig.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
//使用SqlSessionFactoryBuilder創建sessionFactory
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
}
@Test
public void testFindUserById() throws Exception {
//獲取session
SqlSession session = sqlSessionFactory.openSession();
//獲取mapper接口的代理對象
UserMapper userMapper = session.getMapper(UserMapper.class);
//調用代理對象方法
User user = userMapper.findUserById(1);
System.out.println(user);
//關閉session
session.close();
}
}