The Tomcat connector configured to listen on port 8080 failed to start.

在学习spring boot时，遇到了一点小问题，8080端口会被占用，错误如下：

org.apache.catalina.LifecycleException: Failed to start component [Connector[HTTP/1.1-8080]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167) ~[tomcat-embed-core-8.5.40.jar:8.5.40]
	at org.apache.catalina.core.StandardService.addConnector(StandardService.java:225) ~[tomcat-embed-core-8.5.40.jar:8.5.40]
	at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.addPreviouslyRemovedConnectors(TomcatEmbeddedServletContainer.java:265) [spring-boot-1.5.21.RELEASE.jar:1.5.21.RELEASE]
	at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.start(TomcatEmbeddedServletContainer.java:208) [spring-boot-1.5.21.RELEASE.jar:1.5.21.RELEASE]
	at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.startEmbeddedServletContainer(EmbeddedWebApplicationContext.java:308) [spring-boot-1.5.21.RELEASE.jar:1.5.21.RELEASE]
	at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.finishRefresh(EmbeddedWebApplicationContext.java:147) [spring-boot-1.5.21.RELEASE.jar:1.5.21.RELEASE]
	at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:545) [spring-context-4.3.24.RELEASE.jar:4.3.24.RELEASE]
	at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:124) [spring-boot-1.5.21.RELEASE.jar:1.5.21.RELEASE]
	at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) [spring-boot-1.5.21.RELEASE.jar:1.5.21.RELEASE]
	at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) [spring-boot-1.5.21.RELEASE.jar:1.5.21.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) [spring-boot-1.5.21.RELEASE.jar:1.5.21.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118) [spring-boot-1.5.21.RELEASE.jar:1.5.21.RELEASE]
	at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107) [spring-boot-1.5.21.RELEASE.jar:1.5.21.RELEASE]
	at com.example.springboosthelloworld.SpringBoostHelloworldApplication.main(SpringBoostHelloworldApplication.java:10) [classes/:na]
Caused by: org.apache.catalina.LifecycleException: Protocol handler start failed
	at org.apache.catalina.connector.Connector.startInternal(Connector.java:1020) ~[tomcat-embed-core-8.5.40.jar:8.5.40]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ~[tomcat-embed-core-8.5.40.jar:8.5.40]
	... 13 common frames omitted
Caused by: java.net.BindException: Address already in use: bind
	at sun.nio.ch.Net.bind0(Native Method) ~[na:1.8.0_181]
	at sun.nio.ch.Net.bind(Net.java:433) ~[na:1.8.0_181]
	at sun.nio.ch.Net.bind(Net.java:425) ~[na:1.8.0_181]
	at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223) ~[na:1.8.0_181]
	at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74) ~[na:1.8.0_181]
	at org.apache.tomcat.util.net.NioEndpoint.bind(NioEndpoint.java:219) ~[tomcat-embed-core-8.5.40.jar:8.5.40]
	at org.apache.tomcat.util.net.AbstractEndpoint.start(AbstractEndpoint.java:1178) ~[tomcat-embed-core-8.5.40.jar:8.5.40]
	at org.apache.coyote.AbstractProtocol.start(AbstractProtocol.java:591) ~[tomcat-embed-core-8.5.40.jar:8.5.40]
	at org.apache.catalina.connector.Connector.startInternal(Connector.java:1018) ~[tomcat-embed-core-8.5.40.jar:8.5.40]
	... 14 common frames omitted

2019-06-29 19:53:21.002  INFO 6152 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2019-06-29 19:53:21.060  INFO 6152 --- [           main] utoConfigurationReportLoggingInitializer : 

Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2019-06-29 19:53:21.071 ERROR 6152 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 

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

可以在配置文件application.properties中更改一个server端口
server.port = 8081；
即可解决