SpringBoot第一種啟動方式

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
//@RestController 修飾的類下所有方法，全部都是返回json格式，這樣就不用再方法上加@ResponseBody
 

@EnableAutoConfiguration
//@EnableAutoConfiguration 開啟自動配置 裝配到spring容器中
public class IndexController {
@RequestMapping("/demo")
    public  String index(){
        return  "hello word";
    }

    public static void main(String[] args) {
    //程序入口，啟動類
        SpringApplication.run(IndexController.class
 
,args);
    }

}

SpringBoot第二種啟動方式

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.ComponentScan;

@ComponentScan("com.example.demo.controller")//掃描包
@EnableAutoConfiguration
 
public class App {
    public static void main(String[] args) {
        SpringApplication.run(App.class,args);
    }
}

SpringBoot第三種啟動方式

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

@SpringBootApplication//掃包範圍當前包下的所有子包
//@SpringBootApplication 等同於@ComponentScan("com.example.demo.controller")//掃描包 和@EnableAutoConfiguration
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class,args);
    }
}

SpringBoot三種啟動方式