MyBatis开发Dao层的两种方式（Mapper动态代理方式）

<?  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.xyfer.mapper.UserMapper\">
    <!-- 根据id查询用户 -->
    <select id=\"getUserById\" parameterType=\"int\" resultType=\"com.xyfer.po.User\">
        select * from user where id = #{id}
    </select>
    <!-- 添加用户 -->
    <insert id=\"insertUser\" parameterType=\"com.xyfer.po.User\">
    <selectKey keyProperty=\"id\" order=\"AFTER\" resultType=\"java.lang.Integer\">
        select LAST_INSERT_ID() 
    </selectKey>
      insert into user(username,birthday,sex,address) 
      values(#{username},#{birthday},#{sex},#{address})
    </insert>
    <!-- 修改用户 -->
    <update id=\"updateUser\" parameterType=\"com.xyfer.po.User\">
        update user set username=#{username},birthday=#{birthday},sex=#{sex},address=#{address}
        where id=#{id}
    </update>
    <!-- 删除用户 -->
    <delete id=\"deleteUserById\" parameterType=\"int\">
        delete from user where id=#{id}
    </delete>
    
</mapper>

package com.xyfer.mapper;

import com.xyfer.po.User;

public interface UserMapper {
    
    public User getUserById(int id);   //根据id值查询一个用户
    public void insertUser(User user); //新增一个用户
    public void updateUser(User user); //修改一个用户
    public void deleteUser(int id);    //删除一个用户

}

<mappers>
    <mapper resource=\"UserMapper. \"/>
</mappers>

package com.xyfer.mapper;

import static org.junit.Assert.*;

import java.io.InputStream;
import java.util.Date;

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.xyfer.po.User;

import junit. work.TestCase;

public class UserMapperTest extends TestCase{

    private SqlSessionFactory sqlSessionFactory;
    
    protected void setUp() throws Exception {
        SqlSessionFactoryBuilder sessionFactoryBuilder = new SqlSessionFactoryBuilder();
        InputStream inputStream = Resources.getResourceAsStream(\"SqlMapConfig. \");
        sqlSessionFactory = sessionFactoryBuilder.build(inputStream);
    }


    @Test
    public void testGetUserById() {
        //获取sqlsession
        SqlSession sqlsession = sqlSessionFactory.openSession();
        //获取UserMapper接口代理对象
        UserMapper userMapper = sqlsession.getMapper(UserMapper.class);
        //调用代理对象方法
        User user = userMapper.getUserById(10);
        //打印结果
        System.out.println(user);
        //关闭sqlsession
        sqlsession.close();
    }

    @Test
    public void testInsertUser() {
        //获取sqlsession
        SqlSession sqlsession = sqlSessionFactory.openSession();
        //获取UserMapper接口代理对象
        UserMapper userMapper = sqlsession.getMapper(UserMapper.class);
        //新建一个对象
        User user = new User();
        user.setUsername(\"小谢\");
        user.setSex(\"男\");
        user.setBirthday(new Date());
        user.setAddress(\"浙江省杭州市\");
        //调用代理对象方法
        userMapper.insertUser(user);
        //关闭sqlsession
        sqlsession.close();
    }

    @Test
    public void testUpdateUser() {
        //获取sqlsession
        SqlSession sqlsession = sqlSessionFactory.openSession();
        //获取UserMapper接口代理对象
        UserMapper userMapper = sqlsession.getMapper(UserMapper.class);
        //新建一个对象
        User user = new User();
        user.setUsername(\"小谢\");
        user.setSex(\"男\");
        user.setBirthday(new Date());
        user.setAddress(\"上海市\");
        //调用代理对象方法
        userMapper.updateUser(user);
        //关闭sqlsession
        sqlsession.close();
    }

    @Test
    public void testDeleteUser() {
        //获取sqlsession
        SqlSession sqlsession = sqlSessionFactory.openSession();
        //获取UserMapper接口代理对象
        UserMapper userMapper = sqlsession.getMapper(UserMapper.class);
        //调用代理对象方法
        userMapper.deleteUser(6);
        //关闭sqlsession
        sqlsession.close();
    }

}