springboot使用spring-data-jpa操作MySQL数据库
我们在上一篇搭建了一个简单的springboot应用,这一篇将介绍使用spring-data-jpa操作数据库。
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DROP TABLE IF EXISTS `user_info`; CREATE TABLE `user_info` ( `id` int(11) NOT NULL AUTO_INCREMENT, `username` varchar(255) DEFAULT NULL, `password` varchar(255) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=MyISAM AUTO_INCREMENT=3 DEFAULT CHARSET=utf8; -- ---------------------------- -- Records of user_info -- ---------------------------- INSERT INTO `user_info` VALUES ('1', 'Java之音', '12345'); INSERT INTO `user_info` VALUES ('2', '张无忌', '123'); |
-- ----------------------------
-- Records of user_info
-- ----------------------------
INSERT INTO `user_info` VALUES ('1', 'Java之音', '12345');
INSERT INTO `user_info` VALUES ('2', '张无忌', '123');
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<dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> </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-data-jpa</artifactId>
</dependency>
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spring: datasource: driver-class-name: com.mysql.jdbc.Driver url: jdbc:mysql://localhost:3306/springboot?useUnicode=true&characterEncoding=UTF-8&useSSL=false username: root password: 1011 jpa: show-sql: true |
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package com.javazhiyin; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; /** * Created by 57783 on 2018/7/4. */ @Entity public class UserInfo { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer id; private String username; private String password; public Integer getId() { return id; } public void setId(Integer 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 UserInfo(){ } } |
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
/**
* Created by 57783 on 2018/7/4.
*/
@Entity
public class UserInfo {
@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
private String username;
private String password;
public Integer getId() {
return id;
}
public void setId(Integer 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 UserInfo(){
}
}
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package com.javazhiyin; import org.springframework.data.jpa.repository.JpaRepository; /** * Created by 57783 on 2018/7/4. */ public interface UserInfoRepository extends JpaRepository<UserInfo,Integer>{ } 这里继承了JpaRepository类,其封装了一些对数据库操作的基本方法,我们通过源码查看一下JpaRepository有哪些方法: // // Source code recreated from a .class file by IntelliJ IDEA // (powered by Fernflower decompiler) // 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); <S extends T> Iterable<S> saveAll(Iterable<S> var1); Optional<T> findById(ID var1); boolean existsById(ID var1); Iterable<T> findAll(); Iterable<T> findAllById(Iterable<ID> var1); long count(); void deleteById(ID var1); void delete(T var1); void deleteAll(Iterable<? extends T> var1); void deleteAll(); } |
import org.springframework.data.jpa.repository.JpaRepository;
/**
* Created by 57783 on 2018/7/4.
*/
public interface UserInfoRepository extends JpaRepository<UserInfo,Integer>{
}
这里继承了JpaRepository类,其封装了一些对数据库操作的基本方法,我们通过源码查看一下JpaRepository有哪些方法:
//
// Source code recreated from a .class file by IntelliJ IDEA
// (powered by Fernflower decompiler)
//
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);
<S extends T> Iterable<S> saveAll(Iterable<S> var1);
Optional<T> findById(ID var1);
boolean existsById(ID var1);
Iterable<T> findAll();
Iterable<T> findAllById(Iterable<ID> var1);
long count();
void deleteById(ID var1);
void delete(T var1);
void deleteAll(Iterable<? extends T> var1);
void deleteAll();
}
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package com.javazhiyin; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.*; import java.util.List; /** * Created by 57783 on 2018/7/4. */ @RestController public class UserInfoController { @Autowired private UserInfoRepository userInfoRepository; /** * 查 * @return */ @GetMapping(value = "/list") public List<UserInfo> getUserList(){ return userInfoRepository.findAll(); } /** * 增 * @param username * @param password * @return */ @PostMapping(value = "/addUser") public UserInfo addUser(@RequestParam("username") String username, @RequestParam("password") String password){ UserInfo user = new UserInfo(); user.setUsername(username); user.setPassword(password); return userInfoRepository.save(user); } /** * 改 * @param id * @param username * @param password * @return */ @PutMapping(value = "updUser/{id}") public UserInfo updUser(@PathVariable("id") Integer id, @RequestParam("username") String username, @RequestParam("password") String password){ UserInfo user = new UserInfo(); user.setId(id); user.setUsername(username); user.setPassword(password); return userInfoRepository.save(user); } /** * 删 * @param id */ @DeleteMapping(value = "delUser/{id}") public void delUser(@PathVariable("id") Integer id){ UserInfo user = new UserInfo(); user.setId(id); userInfoRepository.delete(user); } } |
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;
import java.util.List;
/**
* Created by 57783 on 2018/7/4.
*/
@RestController
public class UserInfoController {
@Autowired
private UserInfoRepository userInfoRepository;
/**
* 查
* @return
*/
@GetMapping(value = "/list")
public List<UserInfo> getUserList(){
return userInfoRepository.findAll();
}
/**
* 增
* @param username
* @param password
* @return
*/
@PostMapping(value = "/addUser")
public UserInfo addUser(@RequestParam("username") String username,
@RequestParam("password") String password){
UserInfo user = new UserInfo();
user.setUsername(username);
user.setPassword(password);
return userInfoRepository.save(user);
}
/**
* 改
* @param id
* @param username
* @param password
* @return
*/
@PutMapping(value = "updUser/{id}")
public UserInfo updUser(@PathVariable("id") Integer id,
@RequestParam("username") String username,
@RequestParam("password") String password){
UserInfo user = new UserInfo();
user.setId(id);
user.setUsername(username);
user.setPassword(password);
return userInfoRepository.save(user);
}
/**
* 删
* @param id
*/
@DeleteMapping(value = "delUser/{id}")
public void delUser(@PathVariable("id") Integer id){
UserInfo user = new UserInfo();
user.setId(id);
userInfoRepository.delete(user);
}
}
- GenerationType.TABLE
- GenerationType.SEQUENCE
- GenerationType.IDENTITY
- GenerationType.AUTO
- Repository:最顶层的接口,是一个空的接口,目的是为了统一所有Repository的类型,且能让组件扫描的时候自动识别。
- CrudRepository :是Repository的子接口,提供CRUD的功能
- PagingAndSortingRepository:是CrudRepository的子接口,添加分页和排序的功能
- JpaRepository:是PagingAndSortingRepository的子接口,增加了一些实用的功能,比如:批量操作等。
- JpaSpecificationExecutor:用来做负责查询的接口
- Specification:是Spring Data JPA提供的一个查询规范,要做复杂的查询,只需围绕这个规范来设置查询条件即可