Mybatis基于命名空间完成POJO类增删改查-----Mybatis框架

ゝ一纸荒年。 2024-03-24 20:53 37阅读 0赞

>     在SQL mapper.xml文件中有一个nameSpace,它是用来指定命名空间的
>     用来防止ID重复,sqlSession.selectList("abc.selectAll");
>     应该是namespace.执行id才是正确的写法,本质上mybatis的sqlId的本质写法是加上命名空间的
> 
>     在SQL mapper.xml文件中有一个nameSpace,它是用来指定命名空间的
>     用来防止ID重复,sqlSession.selectList("abc.selectAll");
>     应该是namespace.执行id才是正确的写法,本质上mybatis的sqlId的本质写法是加上命名空间的

>     <?xml version="1.0" encoding="UTF-8" ?>
>     <!DOCTYPE configuration
>             PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
>             "http://mybatis.org/dtd/mybatis-3-config.dtd">
>     <configuration>
>         
>         <settings>
>             <setting name="logImpl" value="SLF4J"/>
>         </settings>
>         <environments default="development">
>             <environment id="development">
>                 <transactionManager type="JDBC" />
>                 <dataSource type="POOLED">
>                     <property name="driver" value="com.mysql.cj.jdbc.Driver" />
>                     <property name="url" value="jdbc:mysql://localhost:13306/powernode" />
>                     <property name="username" value="root" />
>                     <property name="password" value="abc123" />
>                 </dataSource>
>             </environment>
>         </environments>
>         <mappers>
>             
>             <mapper resource="CarMapper.xml"></mapper>
>             <mapper resource="UserMapper.xml"></mapper>
>             
>             
>         </mappers>
>     </configuration>
> 
>     <?xml version="1.0" encoding="UTF-8" ?>
>     <!DOCTYPE configuration
>             PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
>             "http://mybatis.org/dtd/mybatis-3-config.dtd">
>     <configuration>
>         
>         <settings>
>             <setting name="logImpl" value="SLF4J"/>
>         </settings>
>         <environments default="development">
>             <environment id="development">
>                 <transactionManager type="JDBC" />
>                 <dataSource type="POOLED">
>                     <property name="driver" value="com.mysql.cj.jdbc.Driver" />
>                     <property name="url" value="jdbc:mysql://localhost:13306/powernode" />
>                     <property name="username" value="root" />
>                     <property name="password" value="abc123" />
>                 </dataSource>
>             </environment>
>         </environments>
>         <mappers>
>             
>             <mapper resource="CarMapper.xml"></mapper>
>             <mapper resource="UserMapper.xml"></mapper>
>             
>             
>         </mappers>
>     </configuration>

>     <?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="123">
>         
>         <select id="selectAll" resultType="com.powernode.mybatis.pojo.Car">
>             select
>                 id,
>                 car_num as carNum,
>                 brand,
>                 guide_price as guidePrice,
>                 produce_time as produceTime,
>                 car_type as carType
>             from
>                 t_car
>         </select>
>     
>     </mapper>
> 
>     <?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="123">
>         
>         <select id="selectAll" resultType="com.powernode.mybatis.pojo.Car">
>             select
>                 id,
>                 car_num as carNum,
>                 brand,
>                 guide_price as guidePrice,
>                 produce_time as produceTime,
>                 car_type as carType
>             from
>                 t_car
>         </select>
>     
>     </mapper>

>     package com.powernode.mybatis.test;
>     
>     import com.powernode.mybatis.pojo.Car;
>     import com.powernode.mybatis.utils.SqlSessionUtil;
>     import org.apache.ibatis.session.SqlSession;
>     import org.junit.Test;
>     import org.slf4j.Logger;
>     import org.slf4j.LoggerFactory;
>     
>     import java.util.HashMap;
>     import java.util.Iterator;
>     import java.util.List;
>     import java.util.Map;
>     
>     public class CarMapperTest
>     {
>         private static final Logger logger = LoggerFactory.getLogger(CarMapperTest.class);
>         @Test
>         public void TestSelectAll()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSqlSession();
>             //执行SQL语句
>             List<Object> selectAll = sqlSession.selectList("selectAll");
>             for (int i = 0; i < selectAll.size(); i++)
>             {
>                 logger.info(selectAll.toString());
>             }
>             Iterator iterator = selectAll.iterator();
>             while (iterator.hasNext())
>             {
>                 logger.info(iterator.next().toString());
>             }
>             selectAll.forEach(car -> logger.info(car.toString()));
>             sqlSession.close();
>         }
>         @Test
>         public void TestInsertCar()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSqlSession();
>             //前端传过来数据了,用MAP封装
>             Map<String,Object> map = new HashMap<>();
>             map.put("car_num","1111");
>             map.put("brand","比亚迪汉");
>             map.put("guide_price","10.0");
>             map.put("produce_time","2020-11-11");
>             map.put("car_type","新能源");
>             //执行sql语句,insert(sqlID,一个对象用来封装数据)
>             //两个参数,一个是sqlId,一个是数据封装的对象
>             //用这个封装了数据的对象来传值
>             //这个对象就体现了ORM(对象关系映射)
>             int insert = sqlSession.insert("insertCar",map);
>             logger.info("" + insert);
>             sqlSession.commit();
>             sqlSession.close();
>         }
>         @Test
>         public void TestInsertCarByPOJO()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSqlSession();
>             //执行SQL
>             Car car = new Car(null,"3333","比亚迪秦",12.0,"2020-11-11","新能源");
>             int insertCar = sqlSession.insert("insertCar1", car);
>             //ORM对象,我们都是映射,要取值只能是调用get方法
>             logger.info(insertCar == 1?"成功" : "失败");
>             sqlSession.commit();
>             sqlSession.close();
>         }
>         @Test
>         public void TestDeleteById()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSqlSession();
>             //执行SQL语句
>             int deleteById = sqlSession.delete("deleteById", 2);
>             logger.info(deleteById == 1?"成功" : "失败");
>             sqlSession.commit();
>             sqlSession.close();
>         }
>         @Test
>         public void TestUpdateById()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSqlSession();
>             Car car = new Car(3L,"3333","比亚迪秦",12.0,"2020-11-11","新能源");
>             int updateById = sqlSession.update("updateById", car);
>             logger.info(updateById == 1?"成功" : "失败");
>             sqlSession.commit();
>             sqlSession.close();
>         }
>         @Test
>         public void TestSelectById()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSqlSession();
>             //执行DQL语句
>             Car car = sqlSession.selectOne("selectById", 5);
>             //mybatis底层执行了select后会返回一个ResultSet结果对象
>             //接下来mybatis应该从ResultSet中取值封装成java对象
>             //封装完成返回一个java对象
>             logger.info(car.toString());
>             sqlSession.close();
>         }
>         @Test
>         public void TestNameSpace()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSqlSession();
>     //        List<Object> selectAll = sqlSession.selectList("selectAll");
>             List<Object> objects = sqlSession.selectList("abc.selectAll");
>             objects.forEach(car -> logger.info(car.toString()));
>             sqlSession.close();
>         }
>     }
> 
>     package com.powernode.mybatis.test;
>     
>     import com.powernode.mybatis.pojo.Car;
>     import com.powernode.mybatis.utils.SqlSessionUtil;
>     import org.apache.ibatis.session.SqlSession;
>     import org.junit.Test;
>     import org.slf4j.Logger;
>     import org.slf4j.LoggerFactory;
>     
>     import java.util.HashMap;
>     import java.util.Iterator;
>     import java.util.List;
>     import java.util.Map;
>     
>     public class CarMapperTest
>     {
>         private static final Logger logger = LoggerFactory.getLogger(CarMapperTest.class);
>         @Test
>         public void TestSelectAll()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSqlSession();
>             //执行SQL语句
>             List<Object> selectAll = sqlSession.selectList("selectAll");
>             for (int i = 0; i < selectAll.size(); i++)
>             {
>                 logger.info(selectAll.toString());
>             }
>             Iterator iterator = selectAll.iterator();
>             while (iterator.hasNext())
>             {
>                 logger.info(iterator.next().toString());
>             }
>             selectAll.forEach(car -> logger.info(car.toString()));
>             sqlSession.close();
>         }
>         @Test
>         public void TestInsertCar()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSqlSession();
>             //前端传过来数据了,用MAP封装
>             Map<String,Object> map = new HashMap<>();
>             map.put("car_num","1111");
>             map.put("brand","比亚迪汉");
>             map.put("guide_price","10.0");
>             map.put("produce_time","2020-11-11");
>             map.put("car_type","新能源");
>             //执行sql语句,insert(sqlID,一个对象用来封装数据)
>             //两个参数,一个是sqlId,一个是数据封装的对象
>             //用这个封装了数据的对象来传值
>             //这个对象就体现了ORM(对象关系映射)
>             int insert = sqlSession.insert("insertCar",map);
>             logger.info("" + insert);
>             sqlSession.commit();
>             sqlSession.close();
>         }
>         @Test
>         public void TestInsertCarByPOJO()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSqlSession();
>             //执行SQL
>             Car car = new Car(null,"3333","比亚迪秦",12.0,"2020-11-11","新能源");
>             int insertCar = sqlSession.insert("insertCar1", car);
>             //ORM对象,我们都是映射,要取值只能是调用get方法
>             logger.info(insertCar == 1?"成功" : "失败");
>             sqlSession.commit();
>             sqlSession.close();
>         }
>         @Test
>         public void TestDeleteById()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSqlSession();
>             //执行SQL语句
>             int deleteById = sqlSession.delete("deleteById", 2);
>             logger.info(deleteById == 1?"成功" : "失败");
>             sqlSession.commit();
>             sqlSession.close();
>         }
>         @Test
>         public void TestUpdateById()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSqlSession();
>             Car car = new Car(3L,"3333","比亚迪秦",12.0,"2020-11-11","新能源");
>             int updateById = sqlSession.update("updateById", car);
>             logger.info(updateById == 1?"成功" : "失败");
>             sqlSession.commit();
>             sqlSession.close();
>         }
>         @Test
>         public void TestSelectById()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSqlSession();
>             //执行DQL语句
>             Car car = sqlSession.selectOne("selectById", 5);
>             //mybatis底层执行了select后会返回一个ResultSet结果对象
>             //接下来mybatis应该从ResultSet中取值封装成java对象
>             //封装完成返回一个java对象
>             logger.info(car.toString());
>             sqlSession.close();
>         }
>         @Test
>         public void TestNameSpace()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSqlSession();
>     //        List<Object> selectAll = sqlSession.selectList("selectAll");
>             List<Object> objects = sqlSession.selectList("abc.selectAll");
>             objects.forEach(car -> logger.info(car.toString()));
>             sqlSession.close();
>         }
>     }