Mybatis中使用萬能的Map傳參實現(xiàn)
在編程中,有可能遇到我們的實體類或者數(shù)據(jù)庫中表的字段或參數(shù)過多的情況,那這時候用Map傳參是比較理想的選擇。
Map的特性是鍵值對應(yīng)的,只要確定了一個鍵key,那么值value可以是任何的數(shù)據(jù),這樣就可以在map內(nèi)存中存入任何數(shù)據(jù)。
下面例子演示在mybatis中結(jié)合Map實現(xiàn)基本的增刪改查
數(shù)據(jù)庫表(fruits)結(jié)構(gòu):
實體類:
package com.pojo.pp1; import java.math.BigDecimal; /** * 簡述: *創(chuàng)建實體 * @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;/** * 簡述: * * @author:LiYansheng * @date:2021/07/20 22:31 * @version: */public interface fruitsDao { /*查詢?nèi)啃畔?/ List<fruits> getfruitsList(); /*通過ID查詢信息*/ fruits getfruitsById(@Param('map') Map<String, Object> map); /*添加信息*/ int addfruits(@Param('map') Map<String, Object> map); /*刪除信息*/ 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 mapperPUBLIC '-//mybatis.org//DTD Mapper 3.0//EN''http://mybatis.org/dtd/mybatis-3-mapper.dtd'><mapper namespace='com.pojo.Dao.fruitsDao'> <select resultType='fruits'>select id,name,price from fruits </select> <select parameterType='Map' resultType='fruits'>select id,name,price from fruits where id=#{map.id}; </select> <insert parameterType='Map' >insert into fruits(id,name,price) values (#{map.id},#{map.name},#{map.price}); </insert> <delete parameterType='Map' >delete from fruits where id=#{map.id}; </delete> <update parameterType='Map' >update fruits set name=#{map.name},price=#{map.price} where id=#{map.id} </update></mapper>
在Test類中測試運行:
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;/** * 簡述: * * @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('刪除信息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(); }}
測試結(jié)果,全部都可以通過
需要注意的地方:
標(biāo)記序號的地方是兩種寫類型的方式
第二種方式需要在項目配置中resources下mybatis-config.xml的文件中加入以下的類型別名:
<typeAliases><typeAlias type='java.util.Map' alias='Map'/></typeAliases>
推薦用第二種方式哦
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