1.搭建一個簡單的Springboot項目，最開始將啟動類main函數與controller放到一個類里，可以正常啟動和訪問，但是將兩個分開再啟動時訪問就會報錯：This application has no explicit mapping for /error, so you are seeing this as a fallback.
2、解決方案
在main函數啟動類上加注解：@SpringBootApplication(scanBasePackages = "com") 問題即可解決。
@SpringBootApplication(scanBasePackages = "com")
@EnableAutoConfiguration
public class Application {
public static void main(String[] args) throws Exception {
SpringApplication.run(Application.class, args);
}
}