SpringBoot系列之Spring Data Jpa集成教程

SpringBoot系列之Spring Data Jpa集成教程

Spring Data Jpa是屬於Spring Data的一個子項目，Spring data項目是一款集成了很多數據操作的項目，其下的子項目有如下圖所示：

官方也有提供了英文版的文檔，具體可以參考Spring data官方文檔

JPA是一個規范，並非具體的實現框架，而Spring Data JPA就是依賴於Hibernate JPA的實現

ok，接着通過例子的方式介紹Springboot集成Spring Data JPA的方法，進行實驗，要先創建一個Initializer工程，如圖：


新建項目后，會自動加上如下配置,，如果你的mysql服務器是5.7版本的，建議指定mysql-connector-java版本，Druid也需要自己加上，pom配置參考：

<properties>
		<java.version>1.8</java.version>
		<druid.version>1.1.2</druid.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-web</artifactId>
		</dependency>

		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>5.1.27</version>
			<scope>runtime</scope>
		</dependency>

		<!-- https://mvnrepository.com/artifact/com.alibaba/druid -->
		<dependency>
			<groupId>com.alibaba</groupId>
			<artifactId>druid</artifactId>
			<version>${druid.version}</version>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
			<exclusions>
				<exclusion>
					<groupId>org.junit.vintage</groupId>
					<artifactId>junit-vintage-engine</artifactId>
				</exclusion>
			</exclusions>
		</dependency>
	</dependencies>

新建數據庫和數據表:

CREATE DATABASE /*!32312 IF NOT EXISTS*/`springboot` /*!40100 DEFAULT CHARACTER SET utf8 */;

USE `springboot`;

/*Table structure for table `sys_user` */

DROP TABLE IF EXISTS `sys_user`;

CREATE TABLE `sys_user` (
  `userId` int(10) NOT NULL,
  `username` varchar(20) NOT NULL,
  `sex` char(10) DEFAULT NULL,
  `password` varchar(10) DEFAULT NULL,
  PRIMARY KEY (`userId`),
  UNIQUE KEY `idx_username` (`username`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

/*Data for the table `sys_user` */

insert  into `sys_user`(`userId`,`username`,`sex`,`password`) values (1,'admin','man','11');

新建一個bean類，代碼：

package com.example.springboot.jpa.entity;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;

import javax.persistence.*;

@Entity
@Table(name = "sys_user")
//Springboot2.2.1集成的Spring data jpa比較新，需要加上如下配置
@JsonIgnoreProperties({"hibernateLazyInitializer","handler"})
public class User{

    @Id //主鍵
    @GeneratedValue(strategy = GenerationType.IDENTITY)//自增主鍵
    private Integer userId;

    @Column(name = "username",length = 20) //這是和數據表對應的一個列
    private String username;

    @Column
    private String sex;

    @Column
    private String password;

    public Integer getUserId() {
        return userId;
    }

    public void setUserId(Integer userId) {
        this.userId = userId;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }
}

實現JpaRepository接口，當然Spring data jpa還提供了很多接口，具體可以參考我之前博客:JPA系列之Spring Data JPA系列之入門教程，本博客只介紹在Springboot集成spring data jpa，具體使用還是需要看我之前博客，才可以再來學習本文

package com.example.springboot.jpa.repository;

import com.example.springboot.jpa.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;


public interface UserRepository extends JpaRepository<User,Integer> {

}

不寫Service類，直接寫個controller類進行測試

package com.example.springboot.jpa.controller;

import com.example.springboot.jpa.entity.User;
import com.example.springboot.jpa.repository.UserRepository;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class UserController {

    @Autowired
    UserRepository userRepository;

    @GetMapping("/user/{userId}")
    public User getUser(@PathVariable("userId") Integer userId){
        User user = userRepository.getOne(userId);
        return user;
    }

    @GetMapping("/user")
    public User insertUser(User user){
        User save = userRepository.save(user);
        return save;
    }

}

application.yml配置，當然還要配置數據庫JDBC和連接池，具體參考我的博客：SpringBoot系列之集成Druid配置數據源監控，yaml不熟悉可以，參考我之前博客：SpringBoot系列之YAML配置用法學習筆記

spring:
  jpa:
      hibernate:
  #     更新或者創建數據表結構
        ddl-auto: update
        naming:
          physical-strategy: org.hibernate.boot.model.naming.PhysicalNamingStrategyStandardImpl
  #    控制台顯示SQL
      show-sql: true

啟動Postman來調試接口，測試通過：

代碼例子下載：github下載鏈接