上一篇使用了JdbcTemplate去訪問數據庫，畢竟使用的是原生的SQL形式，像我這種懶人是肯定不會考慮的了。。 這次記錄下使用JPA來極大的減少我們的代碼量 首先，還是準備好SQL文件

DROP TABLE IF EXISTS users;CREATE TABLE users ( id INT ( 11 ) PRIMARY KEY AUTO_INCREMENT, username VARCHAR ( 255 ) NOT NULL, passwd VARCHAR ( 255 ) ) ENGINE = INNODB DEFAULT CHARSET = utf8;INSERT users VALUES ( NULL, '翠花', '123' ); INSERT users VALUES ( NULL, '王衛國', '123' ); INSERT users VALUES ( NULL, '李小花', '123' ); INSERT users VALUES ( NULL, '王二柱', '123' ); INSERT users VALUES ( NULL, '趙鐵蛋', '123' ); 復制代碼

這次需要用到的依賴

<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><scope>runtime</scope></dependency><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-test</artifactId><scope>test</scope></dependency></dependencies> 復制代碼

User.java

package com.priv.gabriel.entity;import javax.persistence.*;/*** Created with Intellij IDEA.** @Author: Gabriel* @Date: 2018-10-08* @Desciption:*/ @Entity @Table(name = "users") public class User {@Id@GeneratedValue(strategy = GenerationType.IDENTITY)private long id;@Column(nullable = false)private String username;@Column(nullable = false)private String passwd;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 String getPasswd() {return passwd;}public void setPasswd(String passwd) {this.passwd = passwd;} }復制代碼

UserController.java

package com.priv.gabriel.controller;import com.priv.gabriel.entity.User; import com.priv.gabriel.repository.UserRepository; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.PathVariable; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RestController;import java.util.List;/*** Created by Administrator on 2018/10/9.*/ @RestController @RequestMapping("/users") public class UserController {@Autowiredprivate UserRepository userRepository;@RequestMapping(value = "/",method = RequestMethod.GET)public List<User> usersList(){return userRepository.findAll();}@RequestMapping(value = "/" ,method = RequestMethod.PUT)public String updateUser(User user){if(userRepository.save(user) != null){return "修改成功";}else{return "修改失敗";}}@RequestMapping(value = "/{id}",method = RequestMethod.GET)public User selectUserById(@PathVariable long id){return userRepository.findById(id).get();}@RequestMapping(value ="/{id}",method = RequestMethod.DELETE)public String deleteUser(@PathVariable long id){userRepository.deleteById(id);return "刪除成功";}@RequestMapping(value = "/",method = RequestMethod.POST)public String saveUser(User user){System.out.println(userRepository);if(userRepository.save(user) != null){return "新增成功";}else{return "新增失敗";}} }復制代碼

此處就偷個懶不寫service層了，要研究的小朋友還是不要學我哈

UserRepository.java

package com.priv.gabriel.repository;import com.priv.gabriel.entity.User; import org.springframework.data.jpa.repository.JpaRepository; import org.springframework.stereotype.Repository;/*** Created with Intellij IDEA.** @Author: Gabriel* @Date: 2018-10-08* @Desciption:*/ @Repository public interface UserRepository extends JpaRepository<User,Long>{ }復制代碼

使用jpa最大的好處就是你只需要基礎一個JpaRepository接口，其余的都交給jpa自己去處理，我們只負責調用就好了，回到springboot的主題就是

just run

轉載于:https://juejin.im/post/5c1ca9da5188250baa55a076

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