Springboot 在Mybatis中使用HashMap进行增删查改

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​​javascript:void(0)​​）。

先准备一张表，

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： 

 数据库：

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：

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：

数据库：

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：