SpringBoot三种启动方式

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 修饰的类下所有方法，全部都是返回json格式，这样就不用再方法上加@ResponseBody
@EnableAutoConfiguration
//@EnableAutoConfiguration 开启自动配置 装配到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，启动类
        SpringApplication.run(IndexController.class,args);
    }

}

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

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

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

@SpringBootApplication//扫包范围当前包下的所有子包
//@SpringBootApplication 等同于@ComponentScan("com.example.demo.controller")//扫描包 和@EnableAutoConfiguration
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class,args);
    }
}