JPA是Java Persistence API的简称，中文名Java持久层API，是JDK 5.0注解或XML描述对象－关系表的映射关系，并将运行期的实体??对象持久化??到数据库中。
目录
??一、初始化springboot项目??
??二、引入依赖文件??
??三、编写配置文件??
??四、编写测试案例??
??User.java??
??UserDao.java??
??UserService.java??
??UserServiceimpl.java??
??JpaController.java??
??五、运行结果展示??
一、初始化springboot项目
二、引入依赖文件<!– https://mvnrepository.com/artifact/mysql/mysql-connector-java –> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>8.0.27</version> </dependency> <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> <version>2.6.1</version> </dependency> <dependency> <groupId>org.projectlombok</groupId> <artifactId>lombok</artifactId> <optional>true</optional> </dependency>三、编写配置文件
注意：需要提前建立好数据库，表可以不建。
#通用数据源配置spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driverspring.datasource.url=jdbc:mysql://localhost:3306/springboot_jpa?charset=utf8mb4&useSSL=falsespring.datasource.username=rootspring.datasource.password=123456# Hikari 数据源专用配置spring.datasource.hikari.maximum-pool-size=20spring.datasource.hikari.minimum-idle=5# JPA 相关配置spring.jpa.database-platform=org.hibernate.dialect.MySQL5InnoDBDialectspring.jpa.show-sql=truespring.jpa.hibernate.ddl-auto=create四、编写测试案例User.javapackage com.csdn.entity;import lombok.AllArgsConstructor;import lombok.Data;import lombok.NoArgsConstructor;import javax.persistence.*;@Entity@Table(name = “AUTH_USER”) //表名@Data@AllArgsConstructor@NoArgsConstructorpublic class User { @Id //主键ID @GeneratedValue(strategy = GenerationType.IDENTITY) //主键自增 private Long id; @Column(length = 32) //字段最大允许长度 private String username; @Column(length = 32) private String password;}UserDao.javapackage com.csdn.dao;import com.csdn.entity.User;import org.springframework.data.jpa.repository.JpaRepository;import org.springframework.stereotype.Repository;@Repositorypublic interface UserDao extends JpaRepository<User, Long> {}UserService.javapackage com.csdn.service;import com.csdn.entity.User;import java.util.List;public interface UserService { public List<User> users();}UserServiceimpl.javapackage com.csdn.service.impl;import com.csdn.dao.UserDao;import com.csdn.entity.User;import com.csdn.service.UserService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.stereotype.Service;import java.util.List;@Servicepublic class UserServiceimpl implements UserService { @Autowired private UserDao userDao; @Override public List<User> users() { User user1 = new User(1L, “admin1”, “123456”); User user2 = new User(2L, “admin2”, “123456”); userDao.save(user1); userDao.save(user2); List<User> users = userDao.findAll(); return users; }}JpaController.javapackage com.csdn.controller;import com.csdn.entity.User;import com.csdn.service.UserService;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RestController;import java.util.List;@RestControllerpublic class JpaController { @Autowired private UserService userService; @GetMapping(“/users”) public List<User> users() { return userService.users(); }}五、运行结果展示
我们在启动日志中可以看到数据库的创建过程。
然后我们访问：localhost:8080/users
到这里，一个简单的整合过程就完成了。如果本篇文章对你有帮助，请一键三连支持，谢谢。
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