使用idea启动spring boot项目时遇到The Tomcat connector configured to listen on port 8080 failed to start

最近开始学习springboot，而第一步运行就遇到了bug如下图所示

rg.apache.catalina.LifecycleException: Protocol handler start failed
	at org.apache.catalina.connector.Connector.startInternal(Connector.java:1008) ~[tomcat-embed-core-9.0.16.jar:9.0.16]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183) ~[tomcat-embed-core-9.0.16.jar:9.0.16]
	at org.apache.catalina.core.StandardService.addConnector(StandardService.java:226) [tomcat-embed-core-9.0.16.jar:9.0.16]
	at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.addPreviouslyRemovedConnectors(TomcatWebServer.java:259) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.start(TomcatWebServer.java:197) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.startWebServer(ServletWebServerApplicationContext.java:311) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.finishRefresh(ServletWebServerApplicationContext.java:164) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:552) [spring-context-5.1.5.RELEASE.jar:5.1.5.RELEASE]
	at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:142) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:316) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248) [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
	at com.example.springboot.SpringBoot01Application.main(SpringBoot01Application.java:10) [classes/:na]
Caused by: java.net.BindException: Address already in use: bind
	at java.base/sun.nio.ch.Net.bind0(Native Method) ~[na:na]
	at java.base/sun.nio.ch.Net.bind(Net.java:433) ~[na:na]
	at java.base/sun.nio.ch.Net.bind(Net.java:425) ~[na:na]
	at java.base/sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:225) ~[na:na]
	at java.base/sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74) ~[na:na]
	at org.apache.tomcat.util.net.NioEndpoint.initServerSocket(NioEndpoint.java:236) ~[tomcat-embed-core-9.0.16.jar:9.0.16]
	at org.apache.tomcat.util.net.NioEndpoint.bind(NioEndpoint.java:210) ~[tomcat-embed-core-9.0.16.jar:9.0.16]
	at org.apache.tomcat.util.net.AbstractEndpoint.bindWithCleanup(AbstractEndpoint.java:1085) ~[tomcat-embed-core-9.0.16.jar:9.0.16]
	at org.apache.tomcat.util.net.AbstractEndpoint.start(AbstractEndpoint.java:1171) ~[tomcat-embed-core-9.0.16.jar:9.0.16]
	at org.apache.coyote.AbstractProtocol.start(AbstractProtocol.java:568) ~[tomcat-embed-core-9.0.16.jar:9.0.16]
	at org.apache.catalina.connector.Connector.startInternal(Connector.java:1005) ~[tomcat-embed-core-9.0.16.jar:9.0.16]
	... 14 common frames omitted

2019-03-26 17:11:21.707  INFO 8468 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2019-03-26 17:11:21.725  INFO 8468 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2019-03-26 17:11:21.729 ERROR 8468 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

***************************
APPLICATION FAILED TO START
***************************

Description:

The Tomcat connector configured to listen on port 8080 failed to start. The port may already be in use or the connector may be misconfigured.

Action:

Verify the connector's configuration, identify and stop any process that's listening on port 8080, or configure this application to listen on another port.

看完之后我明白了，他说我的8080端口被占用了，我相信大家也是一脸懵逼，我的端口咋着就被占用了，百度最多的就是找到8080端口然后杀死他（参照https://blog.csdn.net/strophe/article/details/80252600），我通过命令进入后如下图所示，内心也不知道这个端口有没有其他影响就没动，于是终于找到了解决办法

我们只需要向  application.properties  文件中添加  server.port=9000（任意一个未被占用的端口号都可以） 即可运行成功

成功截图如下，我们可以看到我设置的9000端口启动成功，这样我们的项目就能运行啦！