Springboot 在Mybatis中使用HashMap进行增删查改

分手后的思念是犯贱 2023-08-17 15:44 64阅读 0赞

前言：使用HashMap，我们可以不写resultMap，不写实体类。

OK，我们直接进入实战案例，准备一个springboot+mybatis的项目（如果没搞懂springboot+mybatis的，可以参考我这篇[https://blog.csdn.net/qq\_35387940/article/details/88048830][https_blog.csdn.net_qq_35387940_article_details_88048830]）。  
  
  
先准备一张表，

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1Mzg3OTQw_size_16_color_FFFFFF_t_70][]

然后新建一个interface，FriendMapper.java：

package com.example.demo.mapper;
    
    import org.apache.ibatis.annotations.Mapper;
    
    import java.util.List;
    import java.util.Map;
    
    /**
     * @Author : JCccc
     * @CreateTime : 2019/9/27
     * @Description :
     **/
    
    @Mapper
    public interface FriendMapper {
    
        int add(Map<String,Object> map);
    
        void deleteById(Map<String,Object> map);
    
        Map<String, Object> queryById(Map<String,Object> map);
    
        int update(Map<String,Object> map);
    
    
    }

然后是service，FriendService.java：

package com.example.demo.service;
    
    import java.util.List;
    import java.util.Map;
    
    /**
     * @Author : JCccc
     * @CreateTime : 2019/9/27
     * @Description :
     **/
    public interface FriendService {
    
    
        int add(Map<String,Object> map);
    
        void deleteById(Map<String,Object> map);
    
        Map<String, Object> queryById(Map<String,Object> map);
    
        int update(Map<String,Object> map);
    }

接着是FriendServiceImpl.java：

package com.example.demo.service.impl;
    
    import com.example.demo.mapper.FriendMapper;
    import com.example.demo.service.FriendService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    
    import java.util.List;
    import java.util.Map;
    
    /**
     * @Author : JCccc
     * @CreateTime : 2019/9/27
     * @Description :
     **/
    @Service
    public class FriendServiceImpl implements FriendService {
       @Autowired
        FriendMapper friendMapper;
        @Override
        public int add(Map<String,Object> map) {
            return friendMapper.add(map);
        }
    
        @Override
        public void deleteById(Map<String,Object> map) {
            friendMapper.deleteById(map);
        }
    
        @Override
        public Map<String, Object> queryById(Map<String,Object> map) {
            return  friendMapper.queryById(map);
        }
    
        @Override
        public int update(Map<String,Object> map) {
            return friendMapper.update(map);
        }
    }

然后是xml，FriendMapper.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.example.demo.mapper.FriendMapper" >
    
    
       <insert id="add" useGeneratedKeys="true" keyProperty="id" keyColumn="id"
              parameterType="java.util.HashMap">
            insert into
            friend(id,name,age,nickName)
            values (#{id},#{name},#{age},#{nickName})
        </insert>
    
    
    
        <select id="queryById" parameterType="java.util.HashMap"
                resultType="java.util.HashMap">
           select *
           from friend
           where id=#{id}
        </select>
    
        <update id="update" useGeneratedKeys="true" keyProperty="id" keyColumn="id"
                parameterType="java.util.HashMap">
          update friend
          set  name=#{name},age=#{age},nickName=#{nickName}
          where id=#{id}
        </update>
    
    
        <delete id="deleteById" parameterType="java.util.HashMap">
            delete
            from friend
            where id=#{id}
        </delete>
    
    
    
    </mapper>

最后是写接口进行测试，

添加接口：

@GetMapping("/add")
        public String addFriend(){
         Map map=new HashMap();
         map.put("name","JCccc");
         map.put("age",12);
         map.put("nickName","Migrant worker");
         int result = friendServiceImpl.add(map);
         Object id = map.get("id");
         System.out.println("id:  "+id);
         return "影响行数为："+result+"\n返回主键是："+id;
     }

调用接口：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1Mzg3OTQw_size_16_color_FFFFFF_t_70 1][]

数据库：

![20190927105543278.png][]  
  
  
剩下的查询，修改，删除接口，测试：  
查询接口：

@GetMapping("/query/{id}")
        public String queryFriend(@PathVariable("id") Integer id){
            Map map=new HashMap();
            map.put("id",id);
            map = friendServiceImpl.queryById(map);
            return map.toString();
        }

调用接口：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1Mzg3OTQw_size_16_color_FFFFFF_t_70 2][]  
  
修改接口：

@GetMapping("/update")
        public String updateFriend(){
            Map map=new HashMap();
            map.put("id",7);
            map.put("name","update");
            map.put("age",12);
            map.put("nickName","update");
            int result = friendServiceImpl.update(map);
            Object id = map.get("id");
            return "影响行数为："+result+"\n返回主键是："+id;
        }

调用接口：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM1Mzg3OTQw_size_16_color_FFFFFF_t_70 3][]

数据库：

![2019092710593153.png][]

删除接口：

@GetMapping("/delete/{id}")
        public void deleteFriend(@PathVariable("id") Integer id){
            Map map=new HashMap();
            map.put("id",id);
            friendServiceImpl.deleteById(map);
    
        }

调用：

![20190927110012804.png][]

好了，到此。  
这个HashMap的使用是需要选择场景的，有些场景使用起来非常舒服方便，有些场景并不然。  
学以致用，致用是需要找到合适的场景用才算致用。

[https_blog.csdn.net_qq_35387940_article_details_88048830]: https://blog.csdn.net/qq_35387940/article/details/88048830
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[20190927105543278.png]: /images/20230810/1cd143764bb44d88990644c22b7f52f8.png
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[2019092710593153.png]: /images/20230810/218bbf853a5643aca02aa523c90c40f8.png
[20190927110012804.png]: /images/20230810/2947c969d04c4181b2d425e04cd9fa49.png