mybatis用selectlist结果OrdersCustom@76b0bfab

Question

MyMapper.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:根标签，namespace：命名空间，随便写，一般保证命名空间唯一 -->
<mapper namespace="MyMapper">
    <!-- statement，内容：sql语句。id：唯一标识，随便写，在同一个命名空间下保持唯一
      resultType：sql语句查询结果集的封装类型,tb_user即为数据库中的表
    -->

    <select id="findOrdersList" resultType="com.zpc.mybatis.OrdersCustom">
        SELECT
        orders.*,
        user.user_name,
        user.user_address
        FROM
        orders, user
        WHERE orders.user_id = user.id
    </select>
    <select id="test" resultType="com.zpc.mybatis.Orders">
        select * from orders where orders.user_id = 3
    </select>
</mapper>

MybatisTest
package com.zpc.mybatis;

import javax.annotation.Resource;
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 java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class MybatisTest {
    public static void main(String[] args) throws IOException {
        //制定配置文件
        String resource = "mybatis-config.xml";
        //读取配置文件
        InputStream inputStream = Resources.getResourceAsStream(resource);
        //构建sqlSessionFactory
        SqlSessionFactory sqlSessionFactory;
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //获取SqlSession
        SqlSession sqlSession = sqlSessionFactory.openSession();

        try {
            //操作CRUD，第一次个参数：制定satement 规则，命名空间.satementID
            //第二个参数:指定传入sql的参数，这里是用户id

            List<OrdersCustom> list = sqlSession.selectList("MyMapper.findOrdersList");
            System.out.println(list);

            Orders orders = sqlSession.selectOne("MyMapper.test");
            System.out.println(orders);

        }finally {
            sqlSession.close();
        }
    }
}

mybatis-config.xml
<?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>
    <properties>
        <property name="driver" value="com.mysql.cj.jdbc.Driver"/>
        <property name="url" value="jdbc:mysql://localhost:3306/ssmdemo?useUnicode=true&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC&amp;
        useUnicode=true&amp;characterEncoding=utf-8&amp;useSSL=FALSE&amp;MultiQueries=true"/>
        <property name="username" value="root"/>
        <property name="password" value="123456"/>
    </properties>
<environments default="development">
    <environment id="development">
        <!-- 事务管理器，JDBC类型的事务管理器 -->
        <transactionManager type="JDBC" />
        <!-- 数据源，池类型的数据源 -->
        <dataSource type="POOLED">
            <property name="driver" value="${driver}" /> <!-- 配置了properties，所以可以直接引用 -->
            <property name="url" value="${url}" />
            <property name="username" value="${username}" />
            <property name="password" value="${password}" />
        </dataSource>
    </environment>
</environments>

    <mappers>
        <mapper resource="mappers/MyMapper.xml"/>
    </mappers>

</configuration>

Orders
package com.zpc.mybatis;

import java.util.Date;

public class Orders {
    private int user_id;
    private int order_num;
    private Date order_time;
    private String order_status;

}

OrdersCustom
package com.zpc.mybatis;

import java.util.Date;

public class OrdersCustom extends Orders{
    private int id;
    private String user_name;
    private String user_address;
    private int user_id;
    private int order_num;
    private Date order_time;
    private String order_status;

}

Answer 1

在实体类中添加toString方法试试