SpringBoot整合JPA

2023-09-27 20:46:40

SpringBoot整合JPA

JPA是什么?

JPA （Java Persistence API）Java持久化API。是一套Sun公司Java官方制定的ORM 方案,是规范，是标准 ，sun公司自己并没有实现

导入Maven

  1. <dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
    <version>2.6.3</version>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <scope>runtime</scope>
</dependency>

  2. 这里用到的是mysql数据库,所以还要导入MySQL的依赖!

配置

  1. application.yaml配置

  2. server:
  port: 80
spring:
  # 配置数据库链接
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    url: jdbc:mysql://localhost:3306
    username: root
    password: root
    driver-class-name: com.mysql.cj.jdbc.Driver
  # jpa主要配置
  jpa:
    show-sql: true # 默认false，在日志里显示执行的sql语句
    database: mysql
    hibernate.ddl-auto: update #指定为update，每次启动项目检测表结构有变化的时候会新增字段，表不存在时会新建，如果指定create，则每次启动项目都会清空数据并删除表，再新建
    properties.hibernate.dialect: org.hibernate.dialect.MySQL5Dialect # 使用JPA创建表时，默认使用的存储引擎是MyISAM，通过指定数据库版本，可以使用InnoDB
    database-platform: org.hibernate.dialect.MySQL5Dialect
    hibernate:
      naming:
        #指定jpa的自动表生成策略，驼峰自动映射为下划线格式
        implicit-strategy: org.hibernate.boot.model.naming.ImplicitNamingStrategyLegacyJpaImpl
        #physical-strategy: org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl

  3. 数据库的用户名和密码哟啊配置自己的!!!

编码

  1. 实体类

  2. 这里还实现了添加数据时自动插入创建时间

    1. package com.blog.demo.entity;


import com.fasterxml.jackson.annotation.JsonFormat;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.data.annotation.CreatedDate;
import org.springframework.data.jpa.domain.support.AuditingEntityListener;

import javax.persistence.*;
import java.io.Serializable;
import java.util.Date;

/**
 * @author mucd
 * @time 2022/2/6 12:46
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
//声明这个是表的实体类
@Entity
//重要
@EntityListeners(AuditingEntityListener.class)
@Table(name = "sys_user")
public class SysUser implements Serializable {
    /**
     * GeneratedValue 指定主键生成策略
     */
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;
    //@Column 是表中的字段名
    @Column(name = "username")
    private String username;
    @Column(name = "password")
    private String password;

    @Column(name = "user_status")
    private String userStatus;

    /**
     * 自动插入创建时间
     */
    @Column(name = "create_date")
    @CreatedDate
    //时间格式
    @JsonFormat(pattern = "yyyy-MM-dd hh:mm:ss")
    private Date createDate;

    public SysUser(Integer id, String username, String password, String userStatus) {
        this.id = id;
        this.username = username;
        this.password = password;
        this.userStatus = userStatus;
    }
}

  3. dao接口

    1. @Repository
public interface SysUserDao extends JpaRepository<SysUser,Integer> {
}

    2. 没错 dao接口什么都不用写,因为常用的增删改查 分页等方法在JpaRepository这个类中都已经被封装好了,我们使用的话直接调用就好了

    3. [外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-7UQbSEPN-1644128207131)(C:\Users\mucd\AppData\Roaming\Typora\typora-user-images\1644126939462.png)]

    4. 如果需要自定义方法的话,那么就在dao中按照规定编写即可.

  4. service类

    1. 为了省事这里的service没有用接口,直接就是用了类.

    2. package com.blog.demo.service;

/**
 * @author mucd
 * @time 2022/2/6 13:10
 */

import com.blog.demo.dao.SysUserDao;
import com.blog.demo.entity.SysUser;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.List;

@Service
public class SysUserService {

    @Resource
    private SysUserDao sysDao;

    /**
     * 查询所有数据
     *
     * @return list
     */
    public List<SysUser> getSysDao() {
        final List<SysUser> all = sysDao.findAll();
        System.out.println("all = " + all);
        return all;
    }


    /**
     * 添加数据
     * @param user user
     * @return object
     */
    public Object addUser(SysUser user) {

        final SysUser sysUser1 = sysDao.saveAndFlush(user);

        System.out.println("save = " + sysUser1);
        return sysUser1;
    }

    /**
    * 定时任务 自动执行
    */
    @Scheduled(cron = " 1/5 * * * * *  ")
    public void excel() {
        final SysUser sysUser = new SysUser();

        sysUser.setUsername("abcd");
        sysUser.setUserStatus("正常");
        sysUser.setPassword("passad");
        System.out.println(this.addUser(sysUser));
    }


}

  5. controller

    1. package com.blog.demo.controller;

import com.blog.demo.entity.SysUser;
import com.blog.demo.r.Result;
import com.blog.demo.service.SysUserService;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;

/**
 * @author mucd
 * @time 2022/2/6 13:11
 */
@RestController
@RequestMapping("/sys")
public class SysUserController {

    @Resource
    private SysUserService userService;

    @GetMapping("/findAll")
    public Object findAll() {
        return new Result<Object>(200, "查询成功", userService.getSysDao());
    }

    @PostMapping("save")
    public Object save() {
        final SysUser sysUser = new SysUser();

        sysUser.setUsername("abcd");
        sysUser.setUserStatus("正常");
        sysUser.setPassword("passad");

        final Object o = userService.addUser(sysUser);
        return new Result<Object>(200, "添加成功", o);
    }
}

  6. 启动类

    1. package com.blog.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
import org.springframework.scheduling.annotation.EnableScheduling;

/**
 * @author mucd
 */
@SpringBootApplication
@EnableJpaAuditing

@EnableScheduling
public class BlogDemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(BlogDemoApplication.class, args);
    }

}

  7. 终于可以测试了,我这里使用的是Apifox

    1. [外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-phlZzmC3-1644128207132)(C:\Users\mucd\AppData\Roaming\Typora\typora-user-images\1644127872681.png)]

    2. 查询ok

    3. 添加会自动添加,因为设置了定时任务,可以看到里面的数据都是定时任务添加进去的,我们还可以手动测试一下添加功能

    4. [外链图片转存失败,源站可能有防盗链机制,建议将图片保存下来直接上传(img-fNCBWRyl-1644128207133)(C:\Users\mucd\AppData\Roaming\Typora\typora-user-images\1644128167381.png)]

ok 简单的整合完成

上一篇：浅谈Spring Data ElasticSearch


下一篇：Spring Boot Serverless 实战 | Serverless 应用的监控与调试