1.使用idea搭建spring boot專案工程，選擇Spring Initializr，選中jdk然後next

2.輸入Group，Artifact，選中Maven Project，然後next

3.選擇web->web 然後next，再finish

4.搭建後項目目錄如下

DemoApplication.java為專案啟動入口

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.
 
SpringBootApplication;

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

在DemoApplication.java所在包或所在包的子包下建立HelloController.java

package com.example.demo;

import org.springframework.web.bind.
 
annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {
    @RequestMapping("/")
    public String hello(){
        return "hello world!";
    }
}

執行專案，起來後在瀏覽器輸入如下地址即可訪問。