springjpa-crudRepository
2019-05-30 本文已影响19人
bugWriter_y
截图1559220540.png
curdRepository继承自Repository，同时实现了基本的增删改查方法
package org.springframework.data.repository;
import java.util.Optional;
@NoRepositoryBean
public interface CrudRepository<T, ID> extends Repository<T, ID> {
<S extends T> S save(S var1);//保存
Optional<T> findById(ID var1);//id查询
boolean existsById(ID var1);//是否存在
Iterable<T> findAll();//查询全部
long count();//统计个数
void deleteById(ID var1);//id删除
void deleteAll();//删除全部
...省略
}
下面是一个基本的例子。使用的h2内存数据库。
- pom.xml
<?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 http://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>2.1.5.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.yanglimou</groupId>
<artifactId>jpa-study</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>jpa-study</name>
<description>Demo project for Spring Boot</description>
<properties>
<java.version>1.8</java.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>
<!-- 使用内存数据库 -->
<dependency>
<groupId>com.h2database</groupId>
<artifactId>h2</artifactId>
<scope>runtime</scope>
</dependency>
<!-- 目的是将iterator转成list -->
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-collections4</artifactId>
<version>4.3</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
- application.yaml
spring:
datasource:
# h2数据库的持久化文件地址
url: jdbc:h2:file:~/jpastudy
username: sa
password:
driver-class-name: org.h2.Driver
jpa:
hibernate:
# 自动生成/修改表
ddl-auto: update
# 显示执行的sql语句
show-sql: true
server:
port: 8080
tomcat:
uri-encoding: UTF-8
- JpaStudyApplication.java
package com.yanglimou.jpastudy;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class JpaStudyApplication {
public static void main(String[] args) {
SpringApplication.run(JpaStudyApplication.class, args);
}
}
- UserBean.java
package com.yanglimou.jpastudy.entity;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
@Entity
public class User {
@Id
@GeneratedValue
private Long id;
private String name;
private Integer age;
private String city;
public String getCity() {
return city;
}
public void setCity(String city) {
this.city = city;
}
public Long getId() {
return id;
}
public void setId(Long id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
}
- UserRepository
package com.yanglimou.jpastudy.repository;
import com.yanglimou.jpastudy.entity.User;
import org.springframework.data.repository.CrudRepository;
public interface UserRepository extends CrudRepository<User, Long> {
}
- UserService
package com.yanglimou.jpastudy.service;
import com.yanglimou.jpastudy.entity.User;
import com.yanglimou.jpastudy.repository.UserRepository;
import org.apache.commons.collections4.IteratorUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
import java.util.Optional;
@Service
public class UserService {
@Autowired
private UserRepository userRepository;
public List<User> findAll() {
Iterable<User> all = userRepository.findAll();
List<User> users = IteratorUtils.toList(all.iterator());
return users;
}
public User findById(Long id) {
Optional<User> byId = userRepository.findById(id);
return byId.orElse(null);//如果没有值返回空
}
//因为save方法是根据主键有没有值来进行增加或者修改的
public User add(User user) {
user.setId(null);
User save = userRepository.save(user);
return save;
}
public User update(Long id, User user) {
if (userRepository.existsById(id)) {
user.setId(id);
User save = userRepository.save(user);
return save;
}
return null;
}
public void delete(Long id) {
if (userRepository.existsById(id))
userRepository.deleteById(id);
}
public void deleteAll() {
userRepository.deleteAll();
}
public Long count() {
return userRepository.count();
}
}
- UserController
package com.yanglimou.jpastudy.controller;
import com.yanglimou.jpastudy.entity.User;
import com.yanglimou.jpastudy.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;
@RestController
@RequestMapping("/users")
public class UserController {
@Autowired
private UserService userService;
@GetMapping("")
public List<User> findAll() {
return userService.findAll();
}
@GetMapping("/{id}")
public User findById(@PathVariable Long id) {
return userService.findById(id);
}
@PostMapping("")
public User add(@RequestBody User user) {
return userService.add(user);
}
@PutMapping("/{id}")
public User add(@PathVariable Long id, @RequestBody User user) {
return userService.update(id, user);
}
@DeleteMapping("{id}")
public void delete(@PathVariable Long id) {
userService.delete(id);
}
@DeleteMapping("")
public void deleteAll() {
userService.deleteAll();
}
@GetMapping("/count")
public Long count() {
return userService.count();
}
}
