Spring-Boot: Creating Your First Application

Introduction

Spring Boot is a lightweight framework that can complete most of the configuration work for Spring-based applications. In this tutorial, you will learn how to use Spring Boot's starters, features, and executable JAR file structure to quickly create a Spring-based application that can run directly. This article uses IDEA as the development tool and Gradle as the build tool to create a simple SpringBoot application, without involving database configuration for now.

Creating with IDEA

Create a new project and select Spring Initializr

Next

Configure dependencies The dependencies I selected are all shown on the right. For Web, I selected REST support, which makes it convenient to write REST applications—you can just use mapping. For the database, I selected JDBC and the MySQL driver. (However, they won't be used in the first application.)

The next step is to choose the folder to save the project. I won't take a screenshot here~ Finally, click the 完成 button, and Gradle will start building the project. This process takes a while, so please be patient.

Writing Code

After waiting for Gradle to finish building, you can start writing REST endpoints. The code is as follows.

package cn.deali.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
// 排除引入数据源配置类
@SpringBootApplication(exclude = {DataSourceAutoConfiguration.class})
public class DemoApplication {

    @RequestMapping("/")
    String index() {
        return "hello world";
    }

    @RequestMapping("hello")
    String hello() {
        return "hello";
    }

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

Run & Test

Click Run - Run DemoApplication to run the Spring Boot project.

If everything is normal, take a look at the output in the Run window.

At this point, open a browser and enter http://127.0.0.1:8080 or http://127.0.0.1:8080/hello to see the running result.