Spring Boot整合Spring data增删改查

秒速五厘米 2022-04-24 03:14 259阅读 0赞

## 1.pom.xml ##

<?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>
       <parent>
          <groupId>org.springframework.boot</groupId>
          <artifactId>spring-boot-starter-parent</artifactId>
          <version>2.1.3.RELEASE</version>
          <relativePath/> 
       </parent>
       <groupId>com.mr</groupId>
       <artifactId>spring-data</artifactId>
       <version>0.0.1-SNAPSHOT</version>
       <name>spring-data</name>
       <description>Demo project for Spring Boot</description>
    
       <properties>
          <java.version>1.8</java.version>
       </properties>
    
       <dependencies>
          
          <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-data-jpa</artifactId>
          </dependency>
          
          <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-freemarker</artifactId>
          </dependency>
          
          <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-jdbc</artifactId>
          </dependency>
          
          <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
          </dependency>
          
          <dependency>
             <groupId>mysql</groupId>
             <artifactId>mysql-connector-java</artifactId>
             <scope>runtime</scope>
          </dependency>
          
          <dependency>
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>
             <optional>true</optional>
          </dependency>
          <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
          </dependency>
          
          <dependency>
             <groupId>com.alibaba</groupId>
             <artifactId>druid-spring-boot-starter</artifactId>
             <version>1.1.10</version>
          </dependency>
       </dependencies>
       <build>
          <plugins>
             <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
             </plugin>
          </plugins>
       </build>
    
    </project>
    ``

## 2.application.properties ##

# 连接池类型
    spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
    # 用户名
    spring.datasource.username=用户名
    # 密码
    spring.datasource.password=密码
    # 驱动
    spring.datasource.dbcp2.driver-class-name=com.mysql.jdbc.Driver
    # url
    spring.datasource.url=jdbc:mysql://127.0.0.1:3306/数据库名?serverTimezone=GMT%2B8
    
    # jpa 配型  数据库类型
    spring.jpa.database=mysql
    # 运行时输出sql 语句
    spring.jpa.show-sql=true
    # 建表策略
    spring.jpa.hibernate.ddl-auto=update

## 3.Car.java ##

package com.mr.model;
    
    
    
    
    import lombok.AllArgsConstructor;
    import lombok.Data;
    import lombok.NoArgsConstructor;
    
    import javax.persistence.*;
    
    /**
     * 
     */
    
    @Data
    @Entity
    @Table(name="t_car")
    @AllArgsConstructor
    @NoArgsConstructor
    public class Car {
        @Id
        @GeneratedValue(strategy= GenerationType.IDENTITY)
        private Integer carId;
        @Column(name="car_name")
        private String carName;
        @Column(name="car_price")
        private Integer carPrice;
    }

## 4.ICarService.java ##

import com.mr.model.Car;
    
    /**
     *
     */
    public interface ICarService {
        /**
         * 新增
         * @param car
         */
        void save(Car car);
    
        /**
         * 查询
         * @return
         */
        Iterable<Car> list();
    
        /**
         * 删除
         * @param
         */
        void delete(Integer id);
    
        /**
         *  根据id查询一条数据(2.0后不能使用findOne了)
         * @param
         * @return
         */
        Car findCarById(Integer id);
    
        /**
         * 修改
         * @param car
         */
        void update(Car car);
    }`

## 5.CarServiceImpl.java ##

import com.mr.dao.CarRepository;
    import com.mr.model.Car;
    import com.mr.service.ICarService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import org.springframework.transaction.annotation.Transactional;
    
    
    
    /**
     * 
     */
    @Service(value="carService")
    @Transactional(readOnly=true)
    public class CarServiceImpl implements ICarService {
    
        @Autowired
        private CarRepository carRepository;
        /**
         * 新增
         * @param
         */
        @Override
        @Transactional
        public void save(Car car) {
            carRepository.save(car);
        }
    
        /**
         * 查询
         * @return
         */
        @Override
        public Iterable<Car> list() {
            return carRepository.findAll();
        }
    
        /**
         * 删除
         * @param
         */
        @Override
        @Transactional
    
        public void delete(Integer id) {
            carRepository.deleteById(id);
        }
        //根据id查询一条数据(2.0后不能使用findOne了)
        @Override
        public Car  findCarById(Integer id) {
            return carRepository.findById(id).get();
        }
    
        /**
         * 修改
         * @param
         */
        @Transactional
        @Override
        public void update(Car car) {
            carRepository.save(car);
        }
    
    }

## 6.CarController.java ##

import com.mr.model.Car;
    import com.mr.service.ICarService;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.*;
    
    /**
     *
     */
    @RestController
    public class CarControler {
        @Autowired
        private ICarService carService;
    
        /**
         * 新增
         *
         */
        @RequestMapping("/car/save")
        @ResponseBody
        public String save(){
            Car car=new Car();
            car.setCarName("奥迪A8");
            car.setCarPrice(666666666);
            carService.save(car);
            return "新增成功";
        }
        /**
         * 查询
         *
         */
        @RequestMapping("/car/list")
        public Iterable<Car> list(){
            Iterable<Car> list=carService.list();
            return list;
    
        }
    
        /**
         * 删除
         */
        @RequestMapping("/car/deleteCarById/{id}")
        @ResponseBody
        public String  deleteCarById(@PathVariable(name ="id", required = true) Integer  id){
            carService.delete(id);
            return "删除成功";
        }
    
        //根据id查询一条数据(2.0后不能使用findOne了)
        @GetMapping(value = "/findCarById/{id}")
        public Car findCarById(@PathVariable(name ="id", required = true) Integer id){
            Car car=carService.findCarById(id);
            return car;
    
        }
        /**
         * 修改
         */
        @RequestMapping("/car/update/{id}")
        public String update(@PathVariable Integer id){
            Car car=new Car();
            car.setCarId(id);
            car.setCarName("兰博基尼");
            car.setCarPrice(888888888);
    
            carService.update(car);
            return "修改成功";
        }
    }

## 7.CarRepository.java ##

import com.mr.model.Car;
    import org.springframework.data.repository.CrudRepository;
    
    
    /**
     * 继承CrudRepository<实体类,主键的类型>
     *
    public interface CarRepository extends CrudRepository<Car,Integer> {
    
    }

## 8.CrudRepository.class给提供的 ##

// Source code recreated from a .class file by IntelliJ IDEA
    // (powered by Fernflower decompiler)
    //
    
    package org.springframework.data.repository;
    
    import java.util.Optional;
    
    @NoRepositoryBean
    public interface CrudRepository<T, ID> extends Repository<T, ID> {
        <S extends T> S save(S var1);
    
        <S extends T> Iterable<S> saveAll(Iterable<S> var1);
    
        Optional<T> findById(ID var1);
    
        boolean existsById(ID var1);
    
        Iterable<T> findAll();
    
        Iterable<T> findAllById(Iterable<ID> var1);
    
        long count();
    
        void deleteById(ID var1);
    
        void delete(T var1);
    
        void deleteAll(Iterable<? extends T> var1);
    
        void deleteAll();
    }
    
    注：CrudRepository为我们提供了一下方法：save，saveAll，findById，existsById，findAll，findAllById，deleteById，delete，deleteAll，因此简单的增删改查不需要在持久层写代码
    SpringData是一款持久层框架,和Hibernate使用类似。
    具体使用查看官网：https://docs.spring.io/spring-data/jpa/docs/2.1.0.M3/reference/html/#repositories.custom-implementations