千峰商城-springboot项目搭建-14-关联查询实现
作者：互联网
1.添加实体类Orders.java
package com.qfedu.tkmapperdemo.beans; import lombok.Data;
@Data
public class Orders {
private String orderId;
private Integer userId;
private String receiverName;
private String receiverMobile;
private String receiverAddress;
}
2.添加OrderDAO.java:
package com.qfedu.tkmapperdemo.dao;
import com.qfedu.tkmapperdemo.beans.Orders;
import com.qfedu.tkmapperdemo.general.GeneralDAO;
public interface OrderDAO extends GeneralDAO<Orders> {
}
3.编写UserDAOTest.java:
package com.qfedu.tkmapperdemo.dao;
import com.qfedu.tkmapperdemo.TkmapperDemoApplication;
import com.qfedu.tkmapperdemo.beans.Orders;
import com.qfedu.tkmapperdemo.beans.User;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import tk.mybatis.mapper.entity.Example;
import java.util.List;
@RunWith(SpringRunner.class)
@SpringBootTest(classes = TkmapperDemoApplication.class)
public class UserDAOTest {
@Autowired
private UserDAO userDAO;
@Autowired
private OrderDAO orderDAO;
@Test
public void testSelect(){
//查询用户的同时查询订单
Example example = new Example(User.class);
Example.Criteria criteria = example.createCriteria();
criteria.andEqualTo("username","zhangsan");
//根据用户名查询用户
//1.先根据用户名查询用户信息
List<User> users = userDAO.selectByExample(example);
User user = users.get(0);
//2.再根据用户id到订单表查询订单信息
Example example1 = new Example(Orders.class);
Example.Criteria criteria1 = example1.createCriteria();
criteria1.andEqualTo("userId",user.getUserId());
List<Orders> ordersList = orderDAO.selectByExample(example1);
//3.将查询到的订单集合设置到user中
user.setOrdersList(ordersList);
System.out.println(user);
}
}
4.在User.java中的Id上加上@Id注解。
package com.qfedu.tkmapperdemo.beans;
import io.swagger.annotations.ApiModel;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import javax.persistence.Id;
import javax.persistence.Table;
import java.util.Date;
import java.util.List;
@Data
@NoArgsConstructor
@AllArgsConstructor
@ApiModel(value = "User对象",description = "买家信息")
@Table(name = "users")
public class User {
@Id
private Integer userId;
private String username;
private String password;
private String nickname;
private String realname;
private String userImg;
private String userMobile;
private String userEmail;
private String userSex;
private Date userBirth;
private Date userRegtime;
private Date userModtime;
private List<Orders> ordersList;
}
测试：
方法二：
5.创建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.qfedu.tkmapperdemo.dao.UserDAO">
<resultMap id="userMap" type="User">
<id column="user_id" property="userId"/>
<result column="username" property="username"/>
<result column="password" property="password"/>
<result column="nickname" property="nickname"/>
<result column="realname" property="realname"/>
<result column="user_img" property="userImg"/>
<result column="user_mobile" property="userMobile"/>
<result column="user_email" property="userEmail"/>
<result column="user_sex" property="userSex"/>
<result column="user_birth" property="userBirth"/>
<result column="user_regtime" property="userRegtime"/>
<result column="user_modtime" property="userModtime"/>
<collection property="ordersList" ofType="Orders">
<result column="order_id" property="orderId"/>
<result column="receiver_name" property="receiverName"/>
<result column="receiver_mobile" property="receiverMobile"/>
<result column="receiver_address" property="receiverAddress"/>
</collection>
</resultMap>
<select id="selectByUsername" parameterType="String" resultMap="userMap">
select
u.user_id,
u.username,
u.password,
u.nickname,
u.realname,
u.user_img,
u.user_mobile,
u.user_email,
u.user_sex,
u.user_birth,
u.user_regtime,
u.user_modtime,
o.order_id,
o.receiver_name,
o.receiver_mobile,
o.receiver_address
from users u inner join orders o
on u.user_id = o.user_id
where u.username = #{username}
</select>
</mapper>
6.修改UserDAOTest.java:
package com.qfedu.tkmapperdemo.dao;
import com.qfedu.tkmapperdemo.TkmapperDemoApplication;
import com.qfedu.tkmapperdemo.beans.Orders;
import com.qfedu.tkmapperdemo.beans.User;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;
import tk.mybatis.mapper.entity.Example;
import java.util.List;
@RunWith(SpringRunner.class)
@SpringBootTest(classes = TkmapperDemoApplication.class)
public class UserDAOTest {
@Autowired
private UserDAO userDAO;
@Autowired
private OrderDAO orderDAO;
@Test
public void testSelect(){
// //查询用户的同时查询订单
// Example example = new Example(User.class);
// Example.Criteria criteria = example.createCriteria();
// criteria.andEqualTo("username","zhangsan");
//
// //根据用户名查询用户
// //1.先根据用户名查询用户信息
// List<User> users = userDAO.selectByExample(example);
// User user = users.get(0);
//
// //2.再根据用户id到订单表查询订单信息
// Example example1 = new Example(Orders.class);
// Example.Criteria criteria1 = example1.createCriteria();
// criteria1.andEqualTo("userId",user.getUserId());
//
// List<Orders> ordersList = orderDAO.selectByExample(example1);
// //3.将查询到的订单集合设置到user中
// user.setOrdersList(ordersList);
//
//
// System.out.println(user);
User user = userDAO.selectByUsername("zhangsan");
System.out.println(user);
}
}
标签：tkmapperdemo,14,private,user,import,千峰,com,Example,springboot 来源： https://www.cnblogs.com/lysboke/p/16403710.html