Mybatis查询结果集返回信息处理之多个Map和单个Map-----Mybatis框架

爱被打了一巴掌 2024-03-03 07:28 44阅读 0赞

>     <?xml version="1.0" encoding="UTF-8"?>
>     <project xmlns="http://maven.apache.org/POM/4.0.0"
>              xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>              xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
>         <modelVersion>4.0.0</modelVersion>
>     
>         <groupId>com.powernode</groupId>
>         <artifactId>Mybatis-008-select</artifactId>
>         <version>1.0-SNAPSHOT</version>
>         <packaging>jar</packaging>
>         <dependencies>
>             <dependency>
>                 <groupId>org.mybatis</groupId>
>                 <artifactId>mybatis</artifactId>
>                 <version>3.5.10</version>
>             </dependency>
>             <dependency>
>                 <groupId>mysql</groupId>
>                 <artifactId>mysql-connector-java</artifactId>
>                 <version>8.0.33</version>
>             </dependency>
>             <dependency>
>                 <groupId>ch.qos.logback</groupId>
>                 <artifactId>logback-classic</artifactId>
>                 <version>1.2.11</version>
>             </dependency>
>             <dependency>
>                 <groupId>junit</groupId>
>                 <artifactId>junit</artifactId>
>                 <version>4.13.2</version>
>                 <scope>test</scope>
>             </dependency>
>         </dependencies>
>         <properties>
>             <maven.compiler.source>17</maven.compiler.source>
>             <maven.compiler.target>17</maven.compiler.target>
>             <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
>         </properties>
>     
>     </project>
> 
>     <?xml version="1.0" encoding="UTF-8"?>
>     <project xmlns="http://maven.apache.org/POM/4.0.0"
>              xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>              xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
>         <modelVersion>4.0.0</modelVersion>
>     
>         <groupId>com.powernode</groupId>
>         <artifactId>Mybatis-008-select</artifactId>
>         <version>1.0-SNAPSHOT</version>
>         <packaging>jar</packaging>
>         <dependencies>
>             <dependency>
>                 <groupId>org.mybatis</groupId>
>                 <artifactId>mybatis</artifactId>
>                 <version>3.5.10</version>
>             </dependency>
>             <dependency>
>                 <groupId>mysql</groupId>
>                 <artifactId>mysql-connector-java</artifactId>
>                 <version>8.0.33</version>
>             </dependency>
>             <dependency>
>                 <groupId>ch.qos.logback</groupId>
>                 <artifactId>logback-classic</artifactId>
>                 <version>1.2.11</version>
>             </dependency>
>             <dependency>
>                 <groupId>junit</groupId>
>                 <artifactId>junit</artifactId>
>                 <version>4.13.2</version>
>                 <scope>test</scope>
>             </dependency>
>         </dependencies>
>         <properties>
>             <maven.compiler.source>17</maven.compiler.source>
>             <maven.compiler.target>17</maven.compiler.target>
>             <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
>         </properties>
>     
>     </project>

>     jdbc.driver=com.mysql.cj.jdbc.Driver
>     jdbc.url=jdbc:mysql://localhost:13306/powernode
>     jdbc.username=root
>     jdbc.password=abc123
> 
>     jdbc.driver=com.mysql.cj.jdbc.Driver
>     jdbc.url=jdbc:mysql://localhost:13306/powernode
>     jdbc.username=root
>     jdbc.password=abc123

>     <?xml version="1.0" encoding="UTF-8" ?>
>     
>     <configuration debug="false">
>         <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
>             <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
>                 <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%n</pattern>
>             </encoder>
>         </appender>
>     
>         <logger name="org.apache.ibatis" level="TRACE">
>     
>         </logger>
>         <logger name="java.sql.Connection" level="DEBUG">
>     
>         </logger>
>         <logger name="java.sql.Statement" level="DEBUG">
>     
>         </logger>
>         <logger name="java.sql.PreparedStatement" level="DEBUG">
>     
>         </logger>
>         
>         
>         <root level="DEBUG">
>             <appender-ref ref="STDOUT">
>     
>             </appender-ref>
>             <appender-ref ref="FILE">
>     
>             </appender-ref>
>         </root>
>     
>     </configuration>
> 
>     <?xml version="1.0" encoding="UTF-8" ?>
>     
>     <configuration debug="false">
>         <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
>             <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
>                 <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%n</pattern>
>             </encoder>
>         </appender>
>     
>         <logger name="org.apache.ibatis" level="TRACE">
>     
>         </logger>
>         <logger name="java.sql.Connection" level="DEBUG">
>     
>         </logger>
>         <logger name="java.sql.Statement" level="DEBUG">
>     
>         </logger>
>         <logger name="java.sql.PreparedStatement" level="DEBUG">
>     
>         </logger>
>         
>         
>         <root level="DEBUG">
>             <appender-ref ref="STDOUT">
>     
>             </appender-ref>
>             <appender-ref ref="FILE">
>     
>             </appender-ref>
>         </root>
>     
>     </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>
>         <properties resource="jdbc.properties"/>
>         <settings>
>             <setting name="logImpl" value="SLF4J"/>
>         </settings>
>         <typeAliases>
>             <package name="com.powernode.mybatis.POJO"/>
>         </typeAliases>
>         <environments default="development">
>             <environment id="development">
>                 <transactionManager type="JDBC"/>
>                 <dataSource type="POOLED">
>                     <property name="driver" value="${jdbc.driver}"/>
>                     <property name="url" value="${jdbc.url}"/>
>                     <property name="username" value="${jdbc.username}"/>
>                     <property name="password" value="${jdbc.password}"/>
>                 </dataSource>
>             </environment>
>         </environments>
>         <mappers>
>             <package name="com.powernode.mybatis.mappers"/>
>         </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>
>         <properties resource="jdbc.properties"/>
>         <settings>
>             <setting name="logImpl" value="SLF4J"/>
>         </settings>
>         <typeAliases>
>             <package name="com.powernode.mybatis.POJO"/>
>         </typeAliases>
>         <environments default="development">
>             <environment id="development">
>                 <transactionManager type="JDBC"/>
>                 <dataSource type="POOLED">
>                     <property name="driver" value="${jdbc.driver}"/>
>                     <property name="url" value="${jdbc.url}"/>
>                     <property name="username" value="${jdbc.username}"/>
>                     <property name="password" value="${jdbc.password}"/>
>                 </dataSource>
>             </environment>
>         </environments>
>         <mappers>
>             <package name="com.powernode.mybatis.mappers"/>
>         </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="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
>                 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="selectAllCar" resultType="Map">
>             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>
>     </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
>                 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="selectAllCar" resultType="Map">
>             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>
>     </mapper>

>     package com.powernode.mybatis.mappers;
>     
>     import com.powernode.mybatis.POJO.Car;
>     
>     import java.util.List;
>     import java.util.Map;
>     
>     public interface CarMapper
>     {
>         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 java.util.List;
>     import java.util.Map;
>     
>     public interface CarMapper
>     {
>         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.POJO;
>     
>     public class Car
>     {
>         //这是一个封装汽车相关信息的普通的java类,数据库表中的字段应该和属性一一对应
>         //为什么使用包装类,因为当我们查值的时候,返回值有可能是null
>         //避免数据不兼容
>         private Long id;
>         private String carNum;
>         private String brand;
>         private Double guidePrice;
>         private String produceTime;
>         private String carType;
>         public Car(){};
>     
>         public Car(Long id, String carNum, String brand, Double guidePrice, String produceTime, String carType) {
>             this.id = id;
>             this.carNum = carNum;
>             this.brand = brand;
>             this.guidePrice = guidePrice;
>             this.produceTime = produceTime;
>             this.carType = carType;
>         }
>     
>         public Long getId() {
>             return id;
>         }
>     
>         public void setId(Long id) {
>             this.id = id;
>         }
>     
>         public String getCarNum() {
>             return carNum;
>         }
>     
>         public void setCarNum(String carNum) {
>             this.carNum = carNum;
>         }
>     
>         public String getBrand() {
>             return brand;
>         }
>     
>         public void setBrand(String brand) {
>             this.brand = brand;
>         }
>     
>         public Double getGuidePrice() {
>             return guidePrice;
>         }
>     
>         public void setGuidePrice(Double guidePrice) {
>             this.guidePrice = guidePrice;
>         }
>     
>         public String getProduceTime() {
>             return produceTime;
>         }
>     
>         public void setProduceTime(String produceTime) {
>             this.produceTime = produceTime;
>         }
>     
>         public String getCarType() {
>             return carType;
>         }
>     
>         public void setCarType(String carType) {
>             this.carType = carType;
>         }
>     
>         @Override
>         public String toString() {
>             return "Car{" +
>                     "id=" + id +
>                     ", carNum='" + carNum + '\'' +
>                     ", brand='" + brand + '\'' +
>                     ", guidePrice=" + guidePrice +
>                     ", produceTime='" + produceTime + '\'' +
>                     ", carType='" + carType + '\'' +
>                     '}';
>         }
>     }
> 
>     package com.powernode.mybatis.POJO;
>     
>     public class Car
>     {
>         //这是一个封装汽车相关信息的普通的java类,数据库表中的字段应该和属性一一对应
>         //为什么使用包装类,因为当我们查值的时候,返回值有可能是null
>         //避免数据不兼容
>         private Long id;
>         private String carNum;
>         private String brand;
>         private Double guidePrice;
>         private String produceTime;
>         private String carType;
>         public Car(){};
>     
>         public Car(Long id, String carNum, String brand, Double guidePrice, String produceTime, String carType) {
>             this.id = id;
>             this.carNum = carNum;
>             this.brand = brand;
>             this.guidePrice = guidePrice;
>             this.produceTime = produceTime;
>             this.carType = carType;
>         }
>     
>         public Long getId() {
>             return id;
>         }
>     
>         public void setId(Long id) {
>             this.id = id;
>         }
>     
>         public String getCarNum() {
>             return carNum;
>         }
>     
>         public void setCarNum(String carNum) {
>             this.carNum = carNum;
>         }
>     
>         public String getBrand() {
>             return brand;
>         }
>     
>         public void setBrand(String brand) {
>             this.brand = brand;
>         }
>     
>         public Double getGuidePrice() {
>             return guidePrice;
>         }
>     
>         public void setGuidePrice(Double guidePrice) {
>             this.guidePrice = guidePrice;
>         }
>     
>         public String getProduceTime() {
>             return produceTime;
>         }
>     
>         public void setProduceTime(String produceTime) {
>             this.produceTime = produceTime;
>         }
>     
>         public String getCarType() {
>             return carType;
>         }
>     
>         public void setCarType(String carType) {
>             this.carType = carType;
>         }
>     
>         @Override
>         public String toString() {
>             return "Car{" +
>                     "id=" + id +
>                     ", carNum='" + carNum + '\'' +
>                     ", brand='" + brand + '\'' +
>                     ", guidePrice=" + guidePrice +
>                     ", produceTime='" + produceTime + '\'' +
>                     ", carType='" + carType + '\'' +
>                     '}';
>         }
>     }

>     package com.powernode.mybatis.utils;
>     
>     import org.apache.ibatis.io.Resources;
>     import org.apache.ibatis.session.SqlSession;
>     import org.apache.ibatis.session.SqlSessionFactory;
>     import org.apache.ibatis.session.SqlSessionFactoryBuilder;
>     
>     import java.io.IOException;
>     
>     public class SqlSessionUtil
>     {
>         private SqlSessionUtil(){};
>         private static SqlSessionFactory sqlSessionFactory;
>         private static ThreadLocal<SqlSession> local = new ThreadLocal<>();
>         static
>         {
>             try
>             {
>                 sqlSessionFactory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis-config.xml"));
>             }
>             catch (IOException e)
>             {
>                 throw new RuntimeException(e);
>             }
>         }
>         public static SqlSession openSession()
>         {
>             SqlSession sqlSession = local.get();
>             if (sqlSession == null)
>             {
>                 sqlSession = sqlSessionFactory.openSession();
>                 local.set(sqlSession);
>             }
>             return sqlSession;
>         }
>         public static void close(SqlSession sqlSession)
>         {
>             if(sqlSession != null)
>             {
>                 sqlSession.close();
>                 local.remove();
>             }
>         }
>     }
> 
>     package com.powernode.mybatis.utils;
>     
>     import org.apache.ibatis.io.Resources;
>     import org.apache.ibatis.session.SqlSession;
>     import org.apache.ibatis.session.SqlSessionFactory;
>     import org.apache.ibatis.session.SqlSessionFactoryBuilder;
>     
>     import java.io.IOException;
>     
>     public class SqlSessionUtil
>     {
>         private SqlSessionUtil(){};
>         private static SqlSessionFactory sqlSessionFactory;
>         private static ThreadLocal<SqlSession> local = new ThreadLocal<>();
>         static
>         {
>             try
>             {
>                 sqlSessionFactory = new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis-config.xml"));
>             }
>             catch (IOException e)
>             {
>                 throw new RuntimeException(e);
>             }
>         }
>         public static SqlSession openSession()
>         {
>             SqlSession sqlSession = local.get();
>             if (sqlSession == null)
>             {
>                 sqlSession = sqlSessionFactory.openSession();
>                 local.set(sqlSession);
>             }
>             return sqlSession;
>         }
>         public static void close(SqlSession sqlSession)
>         {
>             if(sqlSession != null)
>             {
>                 sqlSession.close();
>                 local.remove();
>             }
>         }
>     }

>     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);
>             });
>         }
>     }
> 
>     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);
>             });
>         }
>     }