Caused by: org.springframework.context.ApplicationContextException: Unable to start ServletWebServer

问题：

Caused by: org.springframework.context.ApplicationContextException: Unable to start ServletWebServerApplicationContext due to missing ServletWebServerFactory bean.

原代码：

SpringbootDemoApplication启动类：

@SpringBootApplication
public class SpringbootDemoApplication {

   public static void main(String[] args) {
      SpringApplication.run(HelloController.class, args);
   }
}

HelloController类：

@RestController
public class HelloController {

   @RequestMapping(value = "sayhello", method = RequestMethod.GET)
   public String sayhello() {
      return "Hello SpringBoot !";
   }
}

解决方案：

HelloController加上注解@EnableAutoConfiguration即可。

运行结果：