SpringBoot入门（三）--数据库操作&&Spring-data-jpa的使用

客官°小女子只卖身不卖艺 2022-03-28 11:51 141阅读 0赞

#  #

# 一、添加依赖 #

项目代码：[https://github.com/ffzhihua/springbootdemo][https_github.com_ffzhihua_springbootdemo]

> 数据库框架主要使用了sping-data-jpa

<dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
    
        
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
        </dependency>

### 二、springboot的配置 ###

1、application.yml文件的配置

spring:
      profiles:
        active: dev
    
      #数据库驱动等一些信息
      datasource:
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://127.0.0.1:3306/springboot
        username: root
        password: root
    
      #spring-data-jpa的配置
      jpa:
        hibernate:
          #设置自动创建数据库
          #create：先删除，再创建表，以前表的数据清除
          #update：不删除以前的数据
          #create-drop：当应用停下来的时候删除
          #none：默认什么也不做
          #validate：先验证实体类和表结构是否一致，不一致就会报错
          ddl-auto: create
        #设置显示执行的sql语句
        show-sql: true

2、设置实体类

User.java

package cn.buildworld.springbootdemo;
    
    import org.springframework.web.bind.annotation.PathVariable;
    
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.Id;
    
    /**
     * @Description:用户类
     * @Author: zhihua
     * @Date: 2019/1/9
     */
    @Entity
    public class User {
    
        @Id
        @GeneratedValue
        private Long id;
        private String username;
        private int userage;
    
    
        public Long getId(){
            return id;
        }
    
        public void setId(Long id){
            this.id = id;
        }
    
        public String getUsername(){
            return username;
        }
    
        public void setUsername(String username){
            this.username = username;
        }
    
        public int getUserage(){
            return userage;
        }
    
        public void setUserage(int userage){
            this.userage = userage;
        }
    
    
    }

3、设置dao层接口

UserRespository.java

package cn.buildworld.springbootdemo;
    
    import org.springframework.data.jpa.repository.JpaRepository;
    
    import java.util.List;
    
    /**
     * @Description:dao层接口
     * @Author: zhihua
     * @Date: 2019/1/9
     */
    public interface UserRespository extends JpaRepository<User,Long> {
        /**
         *
         * @param age
         * @return
         */
        public List<User> findByUserage(Integer age);
    }

4、web层的控制器实现我们所需的功能(增删改查)

UserController.java

package cn.buildworld.springbootdemo;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.web.bind.annotation.DeleteMapping;
    import org.springframework.web.bind.annotation.GetMapping;
    import org.springframework.web.bind.annotation.ModelAttribute;
    import org.springframework.web.bind.annotation.PathVariable;
    import org.springframework.web.bind.annotation.PostMapping;
    import org.springframework.web.bind.annotation.PutMapping;
    import org.springframework.web.bind.annotation.RequestBody;
    import org.springframework.web.bind.annotation.RestController;
    
    import java.util.List;
    
    /**
     * @Description:
     * @Author: zhihua
     * @Date: 2019/1/9
     */
    @RestController
    public class UserController {
    
        @Autowired
        private UserRespository userRespository;
    
        @GetMapping("getInfo")
        public List<User> getInfo() {
    
            List<User> all = userRespository.findAll();
            return all;
        }
    
        /**
         * POST方式
         *
         * @return
         */
        @PostMapping(value = "getInfo")
        public String getInfoByPost() {
            return "请使用get方式！";
        }
    
        @PostMapping(value = "adduser")
        public User addUser(@ModelAttribute User user) {
            userRespository.save(user);
            return user;
        }
    
        @GetMapping(value = "user/{id}")
        public User checkUser(@PathVariable("id") Long id) {
            return userRespository.findById(id).orElse(null);
        }
    
        @PutMapping("user/{id}")
        public User updateUser(@PathVariable("id") Long id, User user) {
            user.setId(id);
            userRespository.save(user);
            return userRespository.findById(id).orElse(null);
    
        }
    
        /**
         * DELETE方式删除一个用户
         *
         * @param id
         * @return
         */
        @DeleteMapping(value = "user/{id}")
        public List<User> deleteUser(@PathVariable("id") Long id) {
            userRespository.deleteById(id);
            return userRespository.findAll();
        }
        /**
         * 通过年龄来查询用户信息
         * @param age
         * @return
         */
        @GetMapping(value = "user/age/{age}")
        public List<User> findUserByAge(@PathVariable("age")int age){
            return userRespository.findByUserage(age);
        }
    
    
    }

5、事务

UserService.java

package cn.buildworld.springbootdemo;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import org.springframework.transaction.annotation.Transactional;
    
    /**
     * @Description:
     * @Author: zhihua
     * @Date: 2019/1/10
     */
    @Service
    public class UserService {
        @Autowired
        private UserRespository userRespository;
    
        @Transactional(rollbackFor = Exception.class)
        public void insertTwo(){
    
    
        }
    }

[https_github.com_ffzhihua_springbootdemo]: https://github.com/ffzhihua/springbootdemo