在Mybatis中使用万能的Map传参,实现增删改查

2022-06-30 12:47:35

在编程中,有可能遇到我们的实体类或者数据库中表的字段或参数过多的情况,那这时候用Map传参是比较理想的选择。

Map的特性是键值对应的,只要确定了一个键key,那么值value可以是任何的数据,这样就可以在map内存中存入任何数据。

 下面例子演示在mybatis中结合Map实现基本的增删改查

数据库表(fruits)结构:

实体类:

package com.pojo.pp1;

import java.math.BigDecimal;

/**
 * 简述:
 *创建实体
 * @author:LiYansheng
 * @date:2021/07/20 22:29
 * @version:
 */
public class fruits {
    private int id;
    private String name;
    private BigDecimal price;

    public fruits(int id, String name, BigDecimal price) {
        this.id = id;
        this.name = name;
        this.price = price;
    }

    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 BigDecimal getPrice() {
        return price;
    }

    public void setPrice(BigDecimal price) {
        this.price = price;
    }

    @Override
    public String toString() {
        return "fruits{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", price=" + price +
                '}';
    }
}

Dao接口:

package com.pojo.Dao;

import com.pojo.pp1.fruits;
import org.apache.ibatis.annotations.Param;

import java.util.List;
import java.util.Map;
/**
 * 简述:
 *
 * @author:LiYansheng
 * @date:2021/07/20 22:31
 * @version:
 */
public interface fruitsDao {
    /*查询全部信息*/
    List<fruits> getfruitsList();

    /*通过ID查询信息*/
    fruits getfruitsById(@Param("map") Map<String, Object> map);

    /*添加信息*/
    int addfruits(@Param("map") Map<String, Object> map);

    /*删除信息*/
    int deletefruits(@Param("map") Map<String, Object> map);

    /*修改信息*/
    int updatefruits(@Param("map") Map<String, Object> map);
}

Dao接口.XML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="com.pojo.Dao.fruitsDao">
    <select id="getfruitsList" resultType="fruits">
        select id,name,price from fruits
    </select>

    <select id="getfruitsById" parameterType="Map" resultType="fruits">
        select id,name,price from fruits where id=#{map.id};
    </select>

    <insert id="addfruits" parameterType="Map" >
        insert into fruits(id,name,price) values (#{map.id},#{map.name},#{map.price});
    </insert>

    <delete id="deletefruits" parameterType="Map" >
        delete from fruits where id=#{map.id};
    </delete>

    <update id="updatefruits" parameterType="Map" >
        update  fruits set name=#{map.name},price=#{map.price} where id=#{map.id}
    </update>
</mapper>

 在Test类中测试运行:

package com.pojo.Dao;

import com.pojo.pp1.fruits;
import com.utils.mybatisUtils;

import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import java.math.BigDecimal;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
 * 简述:
 *
 * @author:LiYansheng
 * @date:2021/07/20 22:39
 * @version:
 */
public class fruitsDaoTest {
    @Test
    public void getfruitsListTest() {
        SqlSession sqlSession = mybatisUtils.getSqlSession();
        fruitsDao fruitsDao = sqlSession.getMapper(com.pojo.Dao.fruitsDao.class);
        List<fruits> fruitsList = fruitsDao.getfruitsList();
        for (fruits f : fruitsList) {
            System.out.println(f);
        }
        sqlSession.close();
    }
    @Test
    public void getfruitsByIdTest() {
        SqlSession sqlSession = mybatisUtils.getSqlSession();
        fruitsDao fruitsDao = sqlSession.getMapper(com.pojo.Dao.fruitsDao.class);
        Map<String, Object> map = new HashMap<>();
        map.put("id", 3);
        fruits f = fruitsDao.getfruitsById(map);
        System.out.println(f);
        sqlSession.close();
    }
    @Test
    public void addfruits() {
        SqlSession sqlSession = mybatisUtils.getSqlSession();
        fruitsDao fruitsDao = sqlSession.getMapper(com.pojo.Dao.fruitsDao.class);
        Map<String, Object> map = new HashMap<>();
        map.put("id", 0);
        map.put("name", "watermelon");
        BigDecimal bigDecimal= BigDecimal.valueOf(2);
        map.put("price", bigDecimal);
        int a = fruitsDao.addfruits(map);
        if (a > 0) {
            System.out.println("添加信息ok");
        }
        sqlSession.commit();
        sqlSession.close();
    }
    @Test
    public void deletefruits() {
        SqlSession sqlSession = mybatisUtils.getSqlSession();
        fruitsDao fruitsDao = sqlSession.getMapper(com.pojo.Dao.fruitsDao.class);
        Map<String, Object> map = new HashMap<>();
        map.put("id", 3);
        int a = fruitsDao.deletefruits(map);
        if (a > 0) {
            System.out.println("删除信息ok");
        }
        sqlSession.commit();
        sqlSession.close();
    }
    @Test
    public void updatefruits() {
        SqlSession sqlSession = mybatisUtils.getSqlSession();
        fruitsDao fruitsDao = sqlSession.getMapper(com.pojo.Dao.fruitsDao.class);
        Map<String, Object> map = new HashMap<>();
        map.put("id", 1);
        BigDecimal bigDecimal = BigDecimal.valueOf(5);
        map.put("name", "Big_apple");
        map.put("price", bigDecimal);
        int a = fruitsDao.updatefruits(map);
        if (a > 0) {
            System.out.println("修改信息ok");
        }
        sqlSession.commit();
        sqlSession.close();
    }
}

测试结果,全部都可以通过


需要注意的地方:

标记序号的地方是两种写类型的方式

第二种方式需要在项目配置中resources下mybatis-config.xml的文件中加入以下的类型别名:

<typeAliases>
        <typeAlias type="java.util.Map" alias="Map"/>
</typeAliases>

推荐用第二种方式哦

  • 作者:程序员-小李
  • 原文链接:https://blog.csdn.net/weixin_44107140/article/details/118947185
    更新时间:2022-06-30 12:47:35