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...

亦凉 2023-09-28 23:56 11阅读 0赞

![1b4cce02d45992fd7dbcb4fd443a9fc2.png][]

![903a6c345a3d42d099ef8e36cc786f3b.png][]

![2dd724ffb6123a7e2da3de45de0302d2.png][]

![e946892aeee61acc5d344c59cef03f20.png][]

![9a1041cbfb856632b573a276977b3a7d.png][]

注意：

![b3da8ada94b8d788b6761c9c0fe3af89.png][]

===================================================================

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 +
                    '}';
        }
    }

![fb42fdde51a67fc06c66565cc147b7ae.png][]

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 +
                    '}';
        }
    }

![cc04ff835517b6c80dd5edb0aaafd638.png][]

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>
    
        
        <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>

![dc2d5e920e6dae7237540fb25b3bc0ae.png][]

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();
    
    }

![2397ea15d137b71cc8abc74e5c183fc4.png][]

service接口：

package org.example.service;
    
    import org.example.entity.User2;
    import java.util.List;
    
    public interface User2Service
    {
        List<User2> findAll();
    
    
    }

![d0db9fa510dffa6c492d64bc55d0d225.png][]

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();
    
        }
    
    
    }

![7bce6c6ce3badb295a856682a77adf4e.png][]

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;
        }
    
    
    
    
    }

![a5781262989329b37f80514a80067d1e.png][]

执行：

![7815debf5f602f458ae11170d507f33d.png][]

![e741c5e8f4668a1f4105d1d1eb67b71d.png][]

[1b4cce02d45992fd7dbcb4fd443a9fc2.png]: https://img-blog.csdnimg.cn/img_convert/1b4cce02d45992fd7dbcb4fd443a9fc2.png
[903a6c345a3d42d099ef8e36cc786f3b.png]: https://img-blog.csdnimg.cn/img_convert/903a6c345a3d42d099ef8e36cc786f3b.png
[2dd724ffb6123a7e2da3de45de0302d2.png]: https://img-blog.csdnimg.cn/img_convert/2dd724ffb6123a7e2da3de45de0302d2.png
[e946892aeee61acc5d344c59cef03f20.png]: https://img-blog.csdnimg.cn/img_convert/e946892aeee61acc5d344c59cef03f20.png
[9a1041cbfb856632b573a276977b3a7d.png]: https://img-blog.csdnimg.cn/img_convert/9a1041cbfb856632b573a276977b3a7d.png
[b3da8ada94b8d788b6761c9c0fe3af89.png]: https://img-blog.csdnimg.cn/img_convert/b3da8ada94b8d788b6761c9c0fe3af89.png
[fb42fdde51a67fc06c66565cc147b7ae.png]: https://img-blog.csdnimg.cn/img_convert/fb42fdde51a67fc06c66565cc147b7ae.png
[cc04ff835517b6c80dd5edb0aaafd638.png]: https://img-blog.csdnimg.cn/img_convert/cc04ff835517b6c80dd5edb0aaafd638.png
[dc2d5e920e6dae7237540fb25b3bc0ae.png]: https://img-blog.csdnimg.cn/img_convert/dc2d5e920e6dae7237540fb25b3bc0ae.png
[2397ea15d137b71cc8abc74e5c183fc4.png]: https://img-blog.csdnimg.cn/img_convert/2397ea15d137b71cc8abc74e5c183fc4.png
[d0db9fa510dffa6c492d64bc55d0d225.png]: https://img-blog.csdnimg.cn/img_convert/d0db9fa510dffa6c492d64bc55d0d225.png
[7bce6c6ce3badb295a856682a77adf4e.png]: https://img-blog.csdnimg.cn/img_convert/7bce6c6ce3badb295a856682a77adf4e.png
[a5781262989329b37f80514a80067d1e.png]: https://img-blog.csdnimg.cn/img_convert/a5781262989329b37f80514a80067d1e.png
[7815debf5f602f458ae11170d507f33d.png]: https://img-blog.csdnimg.cn/img_convert/7815debf5f602f458ae11170d507f33d.png
[e741c5e8f4668a1f4105d1d1eb67b71d.png]: https://img-blog.csdnimg.cn/img_convert/e741c5e8f4668a1f4105d1d1eb67b71d.png