Spring boot 项目访问 Mysql 数据库

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Spring boot 项目访问 Mysql 数据库

简介

本文介绍了 Spring boot 项目如何访问 Mysql 数据库，插入，查询和更新 Mysql 数据。

环境准备

• JDK 1.8 +
• Gradle 4 + or Maven 3.2+
• IDEA
• Postman
• Mysql server 8.0.28

创建 Spring boot 项目

需要这些依赖

	<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>

社区版的 IDEA 可以参考 《社区版 IntelliJ IDEA 如何创建Spring boot项目》

旗舰版的 IDEA 可以参考《IntelliJ IDEA Ultimate ( 旗舰版 ) 如何创建Spring boot项目》

配置文件

src/main/resources/application.properties

spring.jpa.hibernate.ddl-auto=update
spring.datasource.url=jdbc:mysql://172.23.176.3:3306/test
spring.datasource.username=test
spring.datasource.password=test
spring.datasource.driver-class-name =com.mysql.jdbc.Driver

开发过程

1. 创建 Entity 模型

该Entity 模型用于映射 Mysql 数据表的字段

src/main/java/com/example/demo/accessingdatamysql/User.java

package com.example.demo.accessingdatamysql;import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;@Entity
public class User {@Id@GeneratedValue(strategy = GenerationType.AUTO)private Integer id;//自增 idprivate String name;private String email;public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getName() {return name;}public void setName(String name) {this.name = name;}public String getEmail() {return email;}public void setEmail(String email) {this.email = email;}
}

2. 创建Repository

src/main/java/com/example/demo/accessingdatamysql/UserRepository.java

package com.example.demo.accessingdatamysql;import org.springframework.data.repository.CrudRepository;// Spring 会自动实现一个名字叫 userRepository 的 Bean
// CRUD refers Create, Read, Update, Deletepublic interface UserRepository extends CrudRepository<User, Integer> {}

3. 创建Controller

src/main/java/com/example/demo/accessingdatamysql/MainController.java

package com.example.demo.accessingdatamysql;import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.*;@Controller
@RequestMapping(path="/demo")
public class MainController {@Autowiredprivate UserRepository userRepository;// 插入@PostMapping(path="/add")public @ResponseBody String addNewUser(@RequestParam String name, @RequestParam String email){User user = new User();user.setName(name);user.setEmail(email);userRepository.save(user);return "Saved";}//查询@GetMapping(path = "/all")public @ResponseBody Iterable<User> getAllUsers() {return userRepository.findAll();}//更新@PostMapping(path="/update")public @ResponseBody String addNewUser(@RequestParam Integer id ,@RequestParam String name, @RequestParam String email){User user = new User();user.setId(id);user.setName(name);user.setEmail(email);userRepository.save(user);return "Updated";}}

4. 创建 Spring boot 启动类

src/main/java/com/example/demo/accessingdatamysql/AccessingDataMysqlApplication.java

package com.example.demo.accessingdatamysql;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication
public class AccessingDataMysqlApplication {public static void main(String[] args) {SpringApplication.run(AccessingDataMysqlApplication.class,args);}
}

启动 Spring boot 项目并postman 测试

1. IDEA 启动 Spring boot 项目

2. Postman 测试插入数据

3. Postman 测试查询数据

4. Postman 测试更新数据