ibatis3中，用Map代替Bean

ibatis3 中 用Map代替pojo类

有一些联合查询，想一条SQL查出想要的数据，不想用主查询+子查询的方式实惠。并且，不想写单独的VO或BO。 所以，就试着用Map来代替pojo类。

1、DB
人物表 t_user
id bigint
name varchar(20)
age int

物品表 t_user_goods
id bigint
goods_name varchar(20)
uid bigint

2、User.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//ibatis.apache.org//DTD Mapper 3.0//EN" "http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd">
<mapper namespace="user">
<resultMap type="java.util.Map" id="userMapper">
<result property="id" column="id" jdbcType="BIGINT"/>
<result property="name" column="name" jdbcType="VARCHAR"/>
<result property="age" column="age" jdbcType="INTEGER"/>
<result property="gid" column="gid" jdbcType="BIGINT"/>
<result property="goodsName" column="goods_name" jdbcType="VARCHAR"/>
</resultMap>


<select id="getUserById" parameterType="int" resultMap="userMapper">
select u.*, g.id gid, g.goods_name from t_user u, t_user_goods g
where u.id=#{id} and g.uid=u.id
</select>
</mapper>

3、sql-map-config.xml
跟 上篇"ibatis3一对多 和 一对一的实现"中的一样

4、IbatisSessionFactory.java
跟 "ibatis3入门学习"中的一样

5、UserDao.java
package com.test.dao;

import java.util.List;
import java.util.Map;
import org.apache.ibatis.session.SqlSession;
import com.bd.dao.IbatisSessionFactory;
import com.test.model.User;

public class UserDao implements UserDaoInte{

public Map<String,Object> getUserById(Long id) {
SqlSession session = IbatisSessionFactory.getSqlSession();
Map<String,Object> user = (Map<String,Object>)session.selectOne("getUserById", id);
session.commit();
session.close();

return user;
}
}


6、测试代码

public static void main(String[] args) {
UserDao dao = new UserDao();

Map<String,Object> u = dao.getUserById(2L);
System.out.println("name:" + u.get("name") );
System.out.println("goods:" + u.get("goodsName"));
}