简介

本文介绍了 Spring boot 项目如何访问 Mysql 数据库，插入和查询 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 安装 spring initializr 后创建 Spring boot

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

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;

    private 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;

public 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 {

    @Autowired
    private UserRepository userRepository;

    @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";

    }

    @GetMapping(path = "/all")
    public @ResponseBody Iterable<User> getAllUsers() {
        return userRepository.findAll();
    }

}

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