Mybatis查询结果集返回信息使用ResultMap实现封装POJO类-----Mybatis框架

痛定思痛。 2024-03-03 07:37 39阅读 0赞

>     <?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.powernode.mybatis.mappers.CarMapper">
>         <select id="selectById" resultType="Car">
>             select
>                 id as id,
>                 car_num as carNum,
>                 brand as brand,
>                 guide_price as guidePrice,
>                 produce_time as produceTime,
>                 car_type as carType
>             from
>                 t_car
>             where
>                 id = #{id};
>         </select>
>         <select id="selectAll" resultType="Car">
>             select
>                 id as id,
>                 car_num as carNum,
>                 brand as brand,
>                 guide_price as guidePrice,
>                 produce_time as produceTime,
>                 car_type as carType
>             from
>                 t_car
>         </select>
>         <select id="selectByBrand" resultType="Car">
>             select
>                 id as id,
>                 car_num as carNum,
>                 brand as brand,
>                 guide_price as guidePrice,
>                 produce_time as produceTime,
>                 car_type as carType
>             from
>                 t_car
>             where
>                 brand like '%${brand}%';
>         </select>
>         <select id="selectByCarId" resultType="Car">
>             select
>                 id as id,
>                 car_num as carNum,
>                 brand as brand,
>                 guide_price as guidePrice,
>                 produce_time as produceTime,
>                 car_type as carType
>             from
>                 t_car
>             where
>                 id = #{id};
>         </select>
>     
>         <select id="selectByIdGetMap" resultType="java.util.Map">
>             select
>                 *
>             from
>                 t_car
>             where
>                 id = #{id};
>         </select>
>         <select id="selectAllCar" resultType="Map">
>             select
>                 *
>             from
>                 t_car;
>         </select>
>     
>         <resultMap id="carResultMap" type="Car">
>     
>     
>     
>             <id property="id" column="id"></id>
>             <result property="carNum" column="car_num" javaType="String" jdbcType="VARCHAR"></result>
>             <result property="brand" column="brand" javaType="String" jdbcType="VARCHAR"></result>
>             <result property="guidePrice" column="guide_price" javaType="Double" jdbcType="DOUBLE"></result>
>             <result property="produceTime" column="produce_time" javaType="String" jdbcType="VARCHAR"></result>
>             <result property="carType" column="car_type" javaType="String" jdbcType="VARCHAR"></result>
>         </resultMap>
>     
>     
>         <select id="selectAllByResultMap" resultMap="carResultMap">
>             select * from t_car;
>         </select>
>         <select id="selectMap" resultType="Map">
>             select
>                 *
>             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="com.powernode.mybatis.mappers.CarMapper">
>         <select id="selectById" resultType="Car">
>             select
>                 id as id,
>                 car_num as carNum,
>                 brand as brand,
>                 guide_price as guidePrice,
>                 produce_time as produceTime,
>                 car_type as carType
>             from
>                 t_car
>             where
>                 id = #{id};
>         </select>
>         <select id="selectAll" resultType="Car">
>             select
>                 id as id,
>                 car_num as carNum,
>                 brand as brand,
>                 guide_price as guidePrice,
>                 produce_time as produceTime,
>                 car_type as carType
>             from
>                 t_car
>         </select>
>         <select id="selectByBrand" resultType="Car">
>             select
>                 id as id,
>                 car_num as carNum,
>                 brand as brand,
>                 guide_price as guidePrice,
>                 produce_time as produceTime,
>                 car_type as carType
>             from
>                 t_car
>             where
>                 brand like '%${brand}%';
>         </select>
>         <select id="selectByCarId" resultType="Car">
>             select
>                 id as id,
>                 car_num as carNum,
>                 brand as brand,
>                 guide_price as guidePrice,
>                 produce_time as produceTime,
>                 car_type as carType
>             from
>                 t_car
>             where
>                 id = #{id};
>         </select>
>     
>         <select id="selectByIdGetMap" resultType="java.util.Map">
>             select
>                 *
>             from
>                 t_car
>             where
>                 id = #{id};
>         </select>
>         <select id="selectAllCar" resultType="Map">
>             select
>                 *
>             from
>                 t_car;
>         </select>
>     
>         <resultMap id="carResultMap" type="Car">
>     
>     
>     
>             <id property="id" column="id"></id>
>             <result property="carNum" column="car_num" javaType="String" jdbcType="VARCHAR"></result>
>             <result property="brand" column="brand" javaType="String" jdbcType="VARCHAR"></result>
>             <result property="guidePrice" column="guide_price" javaType="Double" jdbcType="DOUBLE"></result>
>             <result property="produceTime" column="produce_time" javaType="String" jdbcType="VARCHAR"></result>
>             <result property="carType" column="car_type" javaType="String" jdbcType="VARCHAR"></result>
>         </resultMap>
>     
>     
>         <select id="selectAllByResultMap" resultMap="carResultMap">
>             select * from t_car;
>         </select>
>         <select id="selectMap" resultType="Map">
>             select
>                 *
>             from
>                 t_car
>         </select>
>     </mapper>

>     package com.powernode.mybatis.mappers;
>     
>     import com.powernode.mybatis.POJO.Car;
>     import org.apache.ibatis.annotations.MapKey;
>     
>     import java.util.List;
>     import java.util.Map;
>     
>     public interface CarMapper
>     {
>         List<Car> selectAllByResultMap();
>         //查询所有Car,返回一个Map集合
>         //map集合的Key是主键值,map值是Car对象
>         @MapKey("id")
>         Map<Long,Map<String,Object>> selectMap();
>         List<Map<String,Object>> selectAllCar();
>         Map<String,Object> selectByIdGetMap(Long id);
>         List<Car> selectByCarId(Long id);
>         //模糊查询的对象可能有多个,会出问题吗?
>         Car selectByBrand(String brand);
>         List<Car> selectAll();
>         Car selectById(Long id);
>     }
> 
>     package com.powernode.mybatis.mappers;
>     
>     import com.powernode.mybatis.POJO.Car;
>     import org.apache.ibatis.annotations.MapKey;
>     
>     import java.util.List;
>     import java.util.Map;
>     
>     public interface CarMapper
>     {
>         List<Car> selectAllByResultMap();
>         //查询所有Car,返回一个Map集合
>         //map集合的Key是主键值,map值是Car对象
>         @MapKey("id")
>         Map<Long,Map<String,Object>> selectMap();
>         List<Map<String,Object>> selectAllCar();
>         Map<String,Object> selectByIdGetMap(Long id);
>         List<Car> selectByCarId(Long id);
>         //模糊查询的对象可能有多个,会出问题吗?
>         Car selectByBrand(String brand);
>         List<Car> selectAll();
>         Car selectById(Long id);
>     }

>     package com.powernode.mybatis.Test;
>     
>     import com.powernode.mybatis.POJO.Car;
>     import com.powernode.mybatis.mappers.CarMapper;
>     import com.powernode.mybatis.utils.SqlSessionUtil;
>     import org.apache.ibatis.session.SqlSession;
>     
>     import java.util.List;
>     import java.util.Map;
>     
>     public class Test
>     {
>         @org.junit.Test
>         public void TestPojoSelect()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             Car car = mapper.selectById(5l);
>             System.out.println(car);
>             SqlSessionUtil.close(sqlSession);
>         }
>         @org.junit.Test
>         public void TestSelectAll()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             List<Car> carList = mapper.selectAll();
>             carList.forEach(car -> {
>                 System.out.println(car);
>             });
>             SqlSessionUtil.close(sqlSession);
>         }
>         @org.junit.Test
>         public void TestBrand()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             //会报错,因为返回了多条记录了
>             Car car = mapper.selectByBrand("比亚迪");
>             System.out.println(car);
>             SqlSessionUtil.close(sqlSession);
>         }
>         @org.junit.Test
>         public void TestSelectByCarId()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             List<Car> carList = mapper.selectByCarId(5L);
>             carList.forEach(car -> {
>                 System.out.println(car);
>             });
>             SqlSessionUtil.close(sqlSession);
>         }
>         @org.junit.Test
>         public void TestSelectByIdGetMap()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             Map<String, Object> car = mapper.selectByIdGetMap(5l);
>             System.out.println(car);
>             SqlSessionUtil.close(sqlSession);
>         }
>         @org.junit.Test
>         public void TestselectAllCar()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             List<Map<String, Object>> maps = mapper.selectAllCar();
>             maps.forEach(map ->{
>                 System.out.println(map);
>             });
>         }
>         @org.junit.Test
>         public void TestMap()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             Map<Long, Map<String, Object>> longMapMap = mapper.selectMap();
>             System.out.println(longMapMap);
>             Map<String, Object> map = longMapMap.get(3L);
>             System.out.println(map);
>         }
>         @org.junit.Test
>         public void TestResultMap()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             List<Car> carList = mapper.selectAllByResultMap();
>             carList.forEach(car -> {
>                 System.out.println(car);
>             });
>         }
>         @org.junit.Test
>         public void TestSelectAllByResultMap()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>         }
>     }
> 
>     package com.powernode.mybatis.Test;
>     
>     import com.powernode.mybatis.POJO.Car;
>     import com.powernode.mybatis.mappers.CarMapper;
>     import com.powernode.mybatis.utils.SqlSessionUtil;
>     import org.apache.ibatis.session.SqlSession;
>     
>     import java.util.List;
>     import java.util.Map;
>     
>     public class Test
>     {
>         @org.junit.Test
>         public void TestPojoSelect()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             Car car = mapper.selectById(5l);
>             System.out.println(car);
>             SqlSessionUtil.close(sqlSession);
>         }
>         @org.junit.Test
>         public void TestSelectAll()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             List<Car> carList = mapper.selectAll();
>             carList.forEach(car -> {
>                 System.out.println(car);
>             });
>             SqlSessionUtil.close(sqlSession);
>         }
>         @org.junit.Test
>         public void TestBrand()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             //会报错,因为返回了多条记录了
>             Car car = mapper.selectByBrand("比亚迪");
>             System.out.println(car);
>             SqlSessionUtil.close(sqlSession);
>         }
>         @org.junit.Test
>         public void TestSelectByCarId()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             List<Car> carList = mapper.selectByCarId(5L);
>             carList.forEach(car -> {
>                 System.out.println(car);
>             });
>             SqlSessionUtil.close(sqlSession);
>         }
>         @org.junit.Test
>         public void TestSelectByIdGetMap()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             Map<String, Object> car = mapper.selectByIdGetMap(5l);
>             System.out.println(car);
>             SqlSessionUtil.close(sqlSession);
>         }
>         @org.junit.Test
>         public void TestselectAllCar()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             List<Map<String, Object>> maps = mapper.selectAllCar();
>             maps.forEach(map ->{
>                 System.out.println(map);
>             });
>         }
>         @org.junit.Test
>         public void TestMap()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             Map<Long, Map<String, Object>> longMapMap = mapper.selectMap();
>             System.out.println(longMapMap);
>             Map<String, Object> map = longMapMap.get(3L);
>             System.out.println(map);
>         }
>         @org.junit.Test
>         public void TestResultMap()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>             List<Car> carList = mapper.selectAllByResultMap();
>             carList.forEach(car -> {
>                 System.out.println(car);
>             });
>         }
>         @org.junit.Test
>         public void TestSelectAllByResultMap()
>         {
>             SqlSession sqlSession = SqlSessionUtil.openSession();
>             CarMapper mapper = sqlSession.getMapper(CarMapper.class);
>         }
>     }