spring boot——spring boot的基本配置——spring boot整合mybatis——本地实例运行——MyBatis多表连接——collection多对一

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 注意：

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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数据库：

CREATE TABLE `user2` (
  `id` int ,
  `name` varchar(255) ,
  `age` int 
) ;


insert into user2( id,name,age ) values ( 41,"wang",25);


CREATE TABLE `account` (
  `id` int ,
  `uid` int ,
  `money` int 
) ;

insert into account( id,uid,money) values(1,41,100);
insert into account( id,uid,money) values(2,41,150);

 

 

 

 

 

 

 

 

 

 

 

 

 

 

user2类：

package org.example.entity;

import java.util.List;

public class User2
{
    private int id;
    private String name;
    private int age;

    public List<Account> getAccountList() {
        return accountList;
    }

    public void setAccountList(List<Account> accountList) {
        this.accountList = accountList;
    }

    private List<Account> accountList;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "User2{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", age=" + age +
                ", accountList=" + accountList +
                '}';
    }
}

 

 

 

 

 

 

 

 

 

account类：

package org.example.entity;

public class Account
{
    private int id;
    private int uid;
    private int money;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public int getUid() {
        return uid;
    }

    public void setUid(int uid) {
        this.uid = uid;
    }

    public int getMoney() {
        return money;
    }

    public void setMoney(int money) {
        this.money = money;
    }

    @Override
    public String toString() {
        return "Account{" +
                "id=" + id +
                ", uid=" + uid +
                ", money=" + money +
                '}';
    }
}

 

 

 

 

 

 

 

 

 

 

 

mapper接口文件：

<?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="org.example.mapper.User2Mapper">

    <resultMap id="yiDuDuo" type="org.example.entity.User2">
        <id property="id" column="id"></id>
        <result property="name" column="name"></result>
        <result property="age" column="age"></result>
        <collection property="accountList" ofType="org.example.entity.Account">
            <id property="id" column="aid"></id>
            <result property="uid" column="uid"></result>
            <result property="money" column="money"></result>
        </collection>
    </resultMap>

    <!--查询所有数据-->
    <select id="findAll" resultMap="yiDuDuo">
        select u.*,a.id as aid,a.uid,a.money  from user2 u left outer join account a on u.id = a.uid
    </select>


</mapper>

 

 

 

 

 

 

 

 

 

mapper接口：

package org.example.mapper;

import org.apache.ibatis.annotations.Mapper;
import org.example.entity.User2;
import java.util.List;

@Mapper
public interface User2Mapper
{
    List<User2> findAll();

}

 

 

 

 

 

 

 

 

service接口：

package org.example.service;

import org.example.entity.User2;
import java.util.List;

public interface User2Service
{
    List<User2> findAll();


}

 

 

 

 

 

 

 

 

实现service接口：

package org.example.service.Impl;

import org.example.entity.User2;
import org.example.mapper.User2Mapper;
import org.example.service.User2Service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class User2ServiceImpl implements User2Service
{

    @Autowired
    User2Mapper otherUserMapper;


    public List<User2> findAll()
    {

        return otherUserMapper.findAll();

    }


}

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

控制器：

package org.example.controller;

import org.example.entity.User2;
import org.example.service.User2Service;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class User2Controller
{
    @Autowired
    private User2Service otherService;

    @GetMapping(value = "/31")
    public List<User2> home31()
    {
        // 查询所有用户
        List<User2> users = otherService.findAll();

        for (User2 user : users)
        {
            System.out.println(user);
        }

        return users;
    }




}

 

 

 

 

 

 

 

 

 

执行：