Spring的Jpa是一個非常不錯的持久層框架,可以理解爲就是對Hibrenate進行了封裝,比起Mybatis優點在於不用關注sql語句的編寫。我這案例中使用ResultFul風格來編寫的。
一、搭建SpringBoot項目
導入Jpa的依賴
<!--導入jpa依賴-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<!-- mysql -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.18</version>
</dependency>
全部的pom文件:
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.3.0.M3</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.cxf</groupId>
<artifactId>demo_mall</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo_mall</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<!--springboot-web 整合好了springmvc和spring-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<!--freemaker-->
<!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-freemarker -->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-freemarker</artifactId>
<version>2.1.3.RELEASE</version>
</dependency>
<!--導入jpa依賴-->
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
<groupId>org.projectlombok</groupId>
<artifactId>lombok</artifactId>
<optional>true</optional>
</dependency>
<!-- mysql -->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.18</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>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-test</artifactId>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
<repositories>
<repository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>spring-milestones</id>
<name>Spring Milestones</name>
<url>https://repo.spring.io/milestone</url>
</pluginRepository>
</pluginRepositories>
</project>
application.yml:啓動開發者模式
application-dev.yml
首先,我們要定義實體類,實體類對應一個數據表,其中的屬性對應數據表中的字段。
User:
package com.cxf.demo_mall.api.entity;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
/**
* @author:柴新峯
* @create:2020/4/17
*/
@Entity
public class User {
@Id
@GeneratedValue
private Long id;
@Column(nullable = false, unique = true)
private String userName;
@Column(nullable = false)
private String passWord;
@Column(nullable = false, unique = true)
private String email;
@Column(nullable = false, unique = true)
private String nickName;
@Column(nullable = false)
private String regTime;
public User() {
}
public User(String userName,String passWord,String email,String nickName,String regTime) {
this.userName = userName;
this.passWord = passWord;
this.email = email;
this.nickName = nickName;
this.regTime = regTime;
}
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 getPassWord() {
return passWord;
}
public void setPassWord(String passWord) {
this.passWord = passWord;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public String getNickName() {
return nickName;
}
public void setNickName(String nickName) {
this.nickName = nickName;
}
public String getRegTime() {
return regTime;
}
public void setRegTime(String regTime) {
this.regTime = regTime;
}
}
下面是DAO層,實現用戶的增刪改查方法 :
package com.cxf.demo_mall.api.dao;
import com.cxf.demo_mall.api.entity.User;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import java.util.List;
/**
* @author:柴新峯
* @create:2020/4/19
*/
@Repository
public interface UserDao extends JpaRepository<User,Long> {
}
在這裏我們就能簡單體會到Jpa的強大之處,只需要寫一句userDao.findAll();就可以查到全部數據並放到user列表裏,繼承了JpaRepository倉庫。
接下來,寫UserService:
package com.cxf.demo_mall.api.service;
import com.cxf.demo_mall.api.dao.UserDao;
import com.cxf.demo_mall.api.entity.User;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import javax.transaction.Transactional;
import java.util.List;
/**
* @author:柴新峯
* @create:2020/4/19
*/
@Service
@Transactional
public class UserService {
@Autowired
private UserDao userDao;
/**
* 添加用戶
*/
public void addUser(User user){
userDao.save(user);
}
/**
* 根據id進行修改
* @param user
*/
public void updateUser(User user){
userDao.save(user);
}
/**
* 根據id進行刪除
* @param id
*/
public void deleteUser(Long id){
userDao.deleteById(id);
}
/**
* 查詢所有用戶
* @return
*/
public List<User> listUser(){
return userDao.findAll();
}
/**
* 根據id查詢一條數據
* @param id
* @return
*/
public User findById(Long id){
return userDao.findById(id).get();
}
/**
* 通過姓名查詢用戶集合
* @param username
* @return
*/
// public List<User> findUserName(String username){
// return userDao.findByName(username);
// }
}
Service裏面有個@Transactional是自動開始事務的註解,很方便。
完了後,到Controller類了:
package com.cxf.demo_mall.api.controller;
import com.cxf.demo_mall.api.common.CommonResult;
import com.cxf.demo_mall.api.entity.User;
import com.cxf.demo_mall.api.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;
/**
* @author:柴新峯
* @create:2020/4/19
*/
@RestController
public class UserController {
@Autowired
private UserService userService;
@Autowired
private CommonResult commonResult;
@PostMapping("/addUser")
public CommonResult addUser(User user) {
try {
userService.addUser(user);
return commonResult;
} catch (Exception e) {
e.printStackTrace();
commonResult.setState(500);
commonResult.setMsg("失敗");
return commonResult;
}
}
/**
* 修改用戶
*
* @param user
* @return
*/
@PutMapping(value = "/updateStudent")
public CommonResult updateUser(User user) {
try {
userService.updateUser(user);
return commonResult;
} catch (Exception e) {
e.printStackTrace();
commonResult.setState(500);
commonResult.setMsg("失敗");
return commonResult;
}
}
/**
* 根據id刪除用戶
* @param id
* @return
*/
@DeleteMapping("/deleteUser/{id}")
public CommonResult deleteUserById(@PathVariable(name = "id", required = true) Long id) {
try {
userService.deleteUser(id);
return commonResult;
} catch (Exception e) {
e.printStackTrace();
commonResult.setState(500);
commonResult.setMsg("失敗");
return commonResult;
}
}
/**
* 查詢所有用戶
* @return
*/
@PostMapping("/findAll")
public CommonResult listUser(){
try {
List<User> list = userService.listUser();
commonResult.setData(list);
return commonResult;
} catch (Exception e) {
e.printStackTrace();
commonResult.setState(500);
commonResult.setMsg("查詢錯誤");
commonResult.setData(null);
return commonResult;
}
}
/**
* 根據id查詢一條數據
* @param id
* @return
*/
@PostMapping("/findById/{id}")
public CommonResult findById(@PathVariable(name = "id") Long id){
try {
User user = userService.findById(id);
commonResult.setData(user);
return commonResult;
} catch (Exception e) {
e.printStackTrace();
commonResult.setState(500);
commonResult.setMsg("查詢錯誤哦!");
commonResult.setData(null);
return commonResult;
}
}
}
抽一個全局返回對象類:
package com.cxf.demo_mall.api.common;
import org.springframework.stereotype.Service;
/**
* @author:柴新峯
* @create:2020/4/19
*/
@Service
public class CommonResult {
private Integer state;
private String msg;
private Object data;
public CommonResult() {
this.state = 200;
this.msg = "成功";
}
public CommonResult(Integer state, String msg) {
this.state = state;
this.msg = msg;
}
public CommonResult(Integer state, String msg, Object data) {
this.state = state;
this.msg = msg;
this.data = data;
}
public Integer getState() {
return state;
}
public void setState(Integer state) {
this.state = state;
}
public String getMsg() {
return msg;
}
public void setMsg(String msg) {
this.msg = msg;
}
public Object getData() {
return data;
}
public void setData(Object data) {
this.data = data;
}
}
開始啓動項目:
@SpringBootApplication
public class Application {
public static void main(String[] args) {
SpringApplication.run(Application.class,args);
}
啓動成功,數據庫已經創出了表:
開始測試數據:
1)添加用戶
2)刪除用戶
3)查詢用戶列表
4)根據id查詢一條數據