CrudRepository接口访问数据

拼搏现实的明天。 2022-05-10 06:34 160阅读 0赞

CrudRepository提供了最基本的对实体类的增、删、改、查操作。

示例：CrudRepository接口访问数据

程序清单：/jpa/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>
    
    	<groupId>com.dwx</groupId>
    	<artifactId>jpa</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<packaging>jar</packaging>
    
    	<name>jpa</name>
    	<description></description>
    
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>2.0.5.RELEASE</version>
    		<relativePath/> 
    	</parent>
    
    	<properties>
    		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    		<java.version>1.8</java.version>
    	</properties>
    
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-web</artifactId>
    		</dependency>
    		
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-thymeleaf</artifactId>
    		</dependency>
    		
    		 <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-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    	</dependencies>
    
    	<build>
    		<plugins>
    			<plugin>
    				<groupId>org.springframework.boot</groupId>
    				<artifactId>spring-boot-maven-plugin</artifactId>
    			</plugin>
    		</plugins>
    	</build>
    </project>

程序清单：/jpa/src/main/resources/application.properties

spring.datasource.url=jdbc:mysql://localhost:3306/spring_boot
    spring.datasource.username=root
    spring.datasource.password=root
    spring.datasource.driverClassName=com.mysql.jdbc.Driver
    spring.jpa.database=MySQL
    spring.jpa.show-sql=true
    spring.jpa.hibernate.naming-strategy=org.hibernate.cfg.ImprovedNamingStrategy
    spring.jpa.properties.hibernate.dialect=org.hibernate.dialect.MySQL5Dialect

程序清单：/jpa/src/main/java/com/dwx/bean/User.java

package com.dwx.bean;
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.GenerationType;
    import javax.persistence.Id;
    import javax.persistence.Table;
    @Entity
    @Table(name="t_user")
    public class User {
    	@Id
    	@GeneratedValue(strategy = GenerationType.IDENTITY)
    	private Integer userId;
    	private String userName;
    	private String sex;
    	private Integer age;
    	public Integer getUserId() {
    		return userId;
    	}
    	public void setUserId(Integer userId) {
    		this.userId = userId;
    	}
    	public String getUserName() {
    		return userName;
    	}
    	public void setUserName(String userName) {
    		this.userName = userName;
    	}
    	public String getSex() {
    		return sex;
    	}
    	public void setSex(String sex) {
    		this.sex = sex;
    	}
    	public Integer getAge() {
    		return age;
    	}
    	public void setAge(Integer age) {
    		this.age = age;
    	}
    }

程序清单：/jpa/src/main/java/com/dwx/repository/UserRepository.java

package com.dwx.repository;
    import org.springframework.data.repository.CrudRepository;
    import com.dwx.bean.User;
    public interface UserRepository extends CrudRepository<User, Integer> {
    
    }

程序清单：/jpa/src/main/java/com/dwx/service/UserService.java

package com.dwx.service;
    import java.util.Optional;
    
    import javax.annotation.Resource;
    import javax.transaction.Transactional;
    import org.springframework.stereotype.Service;
    import com.dwx.bean.User;
    import com.dwx.repository.UserRepository;
    @Service
    public class UserService {
    	@Resource
    	private UserRepository userRepository;
    	@Transactional
    	public User save(User user) {
    		return userRepository.save(user);
    	}
    	
    	@Transactional
    	public void delete(Integer id) {
    		userRepository.deleteById(id);
    	}
    	
    	@Transactional
    	public void update(User user) {
    		user.setUserName("露丝");
    		user.setAge(23);
    	}
    	
    	public User getById(Integer id) {
    		Optional<User> op=userRepository.findById(id);
    		return op.get();
    	}
    	
    	public Iterable<User> getAll(){
    		return userRepository.findAll();
    	}
    }

程序清单：/jpa/src/main/java/com/dwx/controller/UserController.java

package com.dwx.controller;
    import javax.annotation.Resource;
    
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import com.dwx.bean.User;
    import com.dwx.service.UserService;
    @RestController
    @RequestMapping("/user")
    public class UserController {
    	@Resource
    	private UserService userService;
    	@RequestMapping("/save")
    	public String save() {
    		User user=new User();
    		user.setUserName("jack");
    		user.setSex("男");
    		user.setAge(22);
    		userService.save(user);
    		return "数据添加成功!";
    	}
    	
    	@RequestMapping("/delete")
    	public String delete() {
    		userService.delete(2);
    		return "删除成功!";
    	}
    		
    	@RequestMapping("/update")
    	public String update() {
    		User user=userService.getById(2);
    		userService.update(user);
    		return "更新成功!";
    	}
    	
    	@RequestMapping("/getAll")
    	public Iterable<User> getAll(){
    		return userService.getAll();
    	}
    }

启动Spring Boot项目，输入以下地址：[http://localhost:8080/user/save][http_localhost_8080_user_save]

![70][]

![70 1][]

测试删除用户，输入以下地址：[http://localhost:8080/user/delete][http_localhost_8080_user_delete]

[![70 2][]][http_localhost_8080_user_delete]

[![70 3][]][http_localhost_8080_user_delete]

测试更改用户，输入以下地址：[http://localhost:8080/user/update][http_localhost_8080_user_update]

![70 4][]

![70 5][]

测试查询用户，输入以下地址：[http://localhost:8080/user/getAll][http_localhost_8080_user_getAll]

![70 6][]

[http_localhost_8080_user_save]: http://localhost:8080/user/save
[70]: /images/20220510/787b94a42f664619b5f2e3c4a7baacdb.png
[70 1]: /images/20220510/e668c0f890754ead9749548ff2e774e5.png
[http_localhost_8080_user_delete]: http://localhost:8080/user/delete
[70 2]: /images/20220510/f37c7d01bed741ab8f82e33f7b267eaf.png
[70 3]: /images/20220510/577ca516534b45b6b5b1ac22a2659b42.png
[http_localhost_8080_user_update]: http://localhost:8080/user/update
[70 4]: /images/20220510/2ffcd49e8675408dbdba58e5dd5609d8.png
[70 5]: /images/20220510/a611cd2681064722bbd9f019a9538472.png
[http_localhost_8080_user_getAll]: http://localhost:8080/user/getAll
[70 6]: /images/20220510/dd6d9dce4b3c4f10a7f738bddbafcaca.png