Mybatis使用insert完成POJO类的ORM映射传参数-----Mybatis框架

水深无声 2024-03-24 20:49 59阅读 0赞

>     CRUD(C:Create,R:Retrieve(查),U:Update,D:Delete)
>     <insert id="insertCar">
>             insert into t_car(id,car_num,brand,guide_price,produce_time,car_type)
>             values(null,'1003','丰田霸道',30.0,'2000-10-11','燃油车')
>         </insert>
>         这样写值写死到配置文件了,这个在实际开发中不能存在的,一定是前端的Form表单提交过来数据
>         将值传给sql语句
>         jdbc中sql语句insert into user(id,username) values(?,?)
>         prepareStatement.setString(1,zhangSan);
>         JDBC中采用的是?,mybatis中采用的是#{}
>         mybatis当中不能采用?占位符,要用#{}来做占位符
>         insert的时候?和#{}是等效的
>         #{}这里写key的值,如果key不存在,就是null
>     java中使用pojo类给sql语句传值,大括号内写pojo类的属性值
>     MYBATIS框架实质上是使用Get方法取出该值的
>     如果使用pojo传值的话,大括号内的写的是get方法的属性名把第一个字母改小写
>     getUserName()改为userName
>     通过XML解析取出需要的属性名字,拼接为getXX方法,通过反射机制执行方法
>     也就是说mybatis在底层给sql的?传值的时候调用了pojo对象的getXX方法
> 
>     CRUD(C:Create,R:Retrieve(查),U:Update,D:Delete)
>     <insert id="insertCar">
>             insert into t_car(id,car_num,brand,guide_price,produce_time,car_type)
>             values(null,'1003','丰田霸道',30.0,'2000-10-11','燃油车')
>         </insert>
>         这样写值写死到配置文件了,这个在实际开发中不能存在的,一定是前端的Form表单提交过来数据
>         将值传给sql语句
>         jdbc中sql语句insert into user(id,username) values(?,?)
>         prepareStatement.setString(1,zhangSan);
>         JDBC中采用的是?,mybatis中采用的是#{}
>         mybatis当中不能采用?占位符,要用#{}来做占位符
>         insert的时候?和#{}是等效的
>         #{}这里写key的值,如果key不存在,就是null
>     java中使用pojo类给sql语句传值,大括号内写pojo类的属性值
>     MYBATIS框架实质上是使用Get方法取出该值的
>     如果使用pojo传值的话,大括号内的写的是get方法的属性名把第一个字母改小写
>     getUserName()改为userName
>     通过XML解析取出需要的属性名字,拼接为getXX方法,通过反射机制执行方法
>     也就是说mybatis在底层给sql的?传值的时候调用了pojo对象的getXX方法

>     <?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="abc">
>         
>         <insert id="insertCar">
>             insert into t_car(id,car_num,brand,guide_price,produce_time,car_type)
>             values(null,#{car_num},#{brand},#{guide_price},#{produce_time},#{car_type})
>     --         底层调用map集合的get方法
>         </insert>
>         <insert id="insertCar1">
>             insert into t_car(id,car_num,brand,guide_price,produce_time,car_type)
>             values(null,#{carNum},#{brand},#{guidePrice},#{produceTime},#{carType})
>             
>         </insert>
>         
>         
>         
>     
>     </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="abc">
>         
>         <insert id="insertCar">
>             insert into t_car(id,car_num,brand,guide_price,produce_time,car_type)
>             values(null,#{car_num},#{brand},#{guide_price},#{produce_time},#{car_type})
>     --         底层调用map集合的get方法
>         </insert>
>         <insert id="insertCar1">
>             insert into t_car(id,car_num,brand,guide_price,produce_time,car_type)
>             values(null,#{carNum},#{brand},#{guidePrice},#{produceTime},#{carType})
>             
>         </insert>
>         
>         
>         
>     
>     </mapper>

>     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.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.Map;
>     
>     public class CarMapperTest
>     {
>         private static final Logger logger = LoggerFactory.getLogger(CarMapperTest.class);
>         @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();
>         }
>     }
> 
>     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.Map;
>     
>     public class CarMapperTest
>     {
>         private static final Logger logger = LoggerFactory.getLogger(CarMapperTest.class);
>         @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();
>         }
>     }