参考 https://blog.csdn.net/qq_25091649/article/details/88429512

 

情况一：在主类直接写controller接口，能够访问到

@SpringBootApplication
@RestController
public class DemoApplication {
	@RequestMapping("/index")
    public String index() {
      
        return "this is index!";
    }


	public static void main(String[] args) {
		//SpringApplication.run(DemoApplication.class, args);
		SpringApplication application = new SpringApplication(DemoApplication.class);
		application.setBannerMode(Mode.OFF);//关闭banner
		application.run(args);
	}

}


情况二：controller类单独写，且controller所在目录低于主类目录，此时也可以访问到

　　

情况三：controller类单独写，且controller所在目录不在住类目录下，此时需要添加注解ComponentScan，里面写入要扫描的包

 

@ComponentScan(basePackages = {"com.xiao","com.example"})
@SpringBootApplication
public class DemoApplication {

	public static void main(String[] args) {
		//SpringApplication.run(DemoApplication.class, args);
		SpringApplication application = new SpringApplication(DemoApplication.class);
		application.setBannerMode(Mode.OFF);//关闭banner
		application.run(args);
	}

}

1、当启动类和controller在同一类中时，需要在该类上添加注解@Controller；

2、当启动类和controller分开时，启动目录高于controller目录，启动类上只有注解@SpringBootApplication；

3、当启动类和controller分开时，如果启动类在某个包下，需要在启动类中增加注解@ComponentScan，配置需要扫描的包名；

 

补充说明：对外的只有主类所在的模块，所以需要把其它模块添加到住类所在模块