1.搭建一个简单的Springboot项目，最开始将启动类main函数与controller放到一个类里，可以正常启动和访问，但是将两个分开再启动时访问就会报错：This application has no explicit mapping for /error, so you are seeing this as a fallback.

@SpringBootApplication(scanBasePackages = "com")

@EnableAutoConfiguration

public class Application {

    public static void main(String[] args) throws Exception {

        SpringApplication.run(Application.class, args);

    }

}