这是控制器的代码

package com.sikidu.demo.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {

   @RequestMapping("/hello")
   @ResponseBody
   public String test(){
       return "HelloSpringBoot";
   }

}

这是网页的结果

Hello word!

这是控制台的结果

Connected to the target VM, address: '127.0.0.1:51251', transport: 'socket'

  .   ____          _            __ _ _

 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \

( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \

 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )

  '  |____| .__|_| |_|_| |_\__, | / / / /

 =========|_|==============|___/=/_/_/_/

 :: Spring Boot ::        (v2.2.6.RELEASE)

2020-04-05 04:28:11.558  INFO 26128 --- [           main] com.sikidu.demo.DemoApplication          : Starting DemoApplication on DESKTOP-44IIV5B with PID 26128 (D:\C\SpringBoot框架的学习\springboot\target\classes started by Administrator in D:\C\SpringBoot框架的学习)

2020-04-05 04:28:11.561  INFO 26128 --- [           main] com.sikidu.demo.DemoApplication          : No active profile set, falling back to default profiles: default

2020-04-05 04:28:12.152  WARN 26128 --- [           main] o.m.s.mapper.ClassPathMapperScanner      : No MyBatis mapper was found in '[com.sikidu.demo]' package. Please check your configuration.

2020-04-05 04:28:12.452  INFO 26128 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)

2020-04-05 04:28:12.459  INFO 26128 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]

2020-04-05 04:28:12.459  INFO 26128 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.33]

2020-04-05 04:28:12.580  INFO 26128 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext

2020-04-05 04:28:12.580  INFO 26128 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 970 ms

2020-04-05 04:28:12.739  INFO 26128 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'

2020-04-05 04:28:12.808  WARN 26128 --- [           main] ion$DefaultTemplateResolverConfiguration : Cannot find template location: classpath:/templates/ (please add some templates or check your Thymeleaf configuration)

2020-04-05 04:28:12.939  INFO 26128 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]

2020-04-05 04:28:12.945  INFO 26128 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.

2020-04-05 04:28:12.948 ERROR 26128 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************

APPLICATION FAILED TO START

***************************

Description:

Web server failed to start. Port 8080 was already in use.

Action:

Identify and stop the process that's listening on port 8080 or configure this application to listen on another port.

2020-04-05 04:28:12.950  INFO 26128 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 'applicationTaskExecutor'

Disconnected from the target VM, address: '127.0.0.1:51251', transport: 'socket'

Process finished with exit code 1