[解决问题] The Tomcat connector configured to listen on port 8080 failed to start.

前言：
今天在启动springboot项目的时候，遇到了这个问题，心里很是奇怪，明明没有项目启动，怎么还占用了8080端口。所以为了排查问题，使用命令行查看端口，并解决了问题。

错误提示

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-8.5.31.jar:8.5.31]
  at org.apache.catalina.core.StandardService.addConnector(StandardService.java:225) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
  at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.addPreviouslyRemovedConnectors(TomcatWebServer.java:256) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
  at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.start(TomcatWebServer.java:198) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
  at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.startWebServer(ServletWebServerApplicationContext.java:300) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
  at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.finishRefresh(ServletWebServerApplicationContext.java:162) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
  at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:553) [spring-context-5.0.7.RELEASE.jar:5.0.7.RELEASE]
  at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:140) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
  at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:759) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
  at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:395) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
  at org.springframework.boot.SpringApplication.run(SpringApplication.java:327) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
  at org.springframework.boot.SpringApplication.run(SpringApplication.java:1255) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
  at org.springframework.boot.SpringApplication.run(SpringApplication.java:1243) [spring-boot-2.0.3.RELEASE.jar:2.0.3.RELEASE]
  at com.ray.lesson5.Lesson5Application.main(Lesson5Application.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-8.5.31.jar:8.5.31]
  at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
  ... 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_161]
  at sun.nio.ch.Net.bind(Net.java:433) ~[na:1.8.0_161]
  at sun.nio.ch.Net.bind(Net.java:425) ~[na:1.8.0_161]
  at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223) ~[na:1.8.0_161]
  at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74) ~[na:1.8.0_161]
  at org.apache.tomcat.util.net.NioEndpoint.bind(NioEndpoint.java:210) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
  at org.apache.tomcat.util.net.AbstractEndpoint.start(AbstractEndpoint.java:1150) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
  at org.apache.coyote.AbstractProtocol.start(AbstractProtocol.java:591) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
  at org.apache.catalina.connector.Connector.startInternal(Connector.java:1018) ~[tomcat-embed-core-8.5.31.jar:8.5.31]
  ... 14 common frames omitted
 
2018-06-26 20:48:00.990  INFO 15332 --- [           main] o.apache.catalina.core.StandardService   : Stopping service [Tomcat]
2018-06-26 20:48:00.997  INFO 15332 --- [           main] ConditionEvaluationReportLoggingListener : 
 
Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2018-06-26 20:48:01.000 ERROR 15332 --- [           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.

解决

查看端口

执行一下命令查看所有端口和PID

netstat

太长了，只截取了有用部分。

根据PID，我们可以查找相应进程。

查找对应进程

tasklist | findstr "10440"

查找如下：

杀死进程

执行一下指令：

taskkill /f /t /im java.exe

此时再重新启动项目就可以了。