文章作者：Tyan
博客：noahsnail.com
使用Mac开发经常会碰到端口被占用的问题，例如作者在使用Spring Boot开发应用时，在启动Application后，忘了关闭，又重启了一次Application，此时会报错误，而且由于重启Application，导致上一次的启动的Application找不到在哪关闭了，此时需要进入终端去查看8080端口对应的进程id，并根据id关闭对应的应用。
错误信息如下图所示：
2016-09-05 09:06:26.734 ERROR 1681 --- [ restartedMain] o.a.coyote.http11.Http11NioProtocol : Failed to start end point associated with ProtocolHandler ["http-nio-8080"]
java.net.BindException: Address already in use
at sun.nio.ch.Net.bind0(Native Method) ~[na:1.8.0_91]
at sun.nio.ch.Net.bind(Net.java:433) ~[na:1.8.0_91]
at sun.nio.ch.Net.bind(Net.java:425) ~[na:1.8.0_91]
at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223) ~[na:1.8.0_91]
at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74) ~[na:1.8.0_91]
at org.apache.tomcat.util.net.NioEndpoint.bind(NioEndpoint.java:340) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.tomcat.util.net.AbstractEndpoint.start(AbstractEndpoint.java:773) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.coyote.AbstractProtocol.start(AbstractProtocol.java:473) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.catalina.connector.Connector.startInternal(Connector.java:986) [tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147) [tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.catalina.core.StandardService.addConnector(StandardService.java:239) [tomcat-embed-core-8.0.33.jar:8.0.33]
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.addPreviouslyRemovedConnectors(TomcatEmbeddedServletContainer.java:194) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.start(TomcatEmbeddedServletContainer.java:151) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.startEmbeddedServletContainer(EmbeddedWebApplicationContext.java:293) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.finishRefresh(EmbeddedWebApplicationContext.java:141) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) [spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1191) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1180) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_91]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_91]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_91]
at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-1.3.5.RELEASE.jar:1.3.5.RELEASE]
2016-09-05 09:06:26.735 ERROR 1681 --- [ restartedMain] o.apache.catalina.core.StandardService : Failed to start connector [Connector[HTTP/1.1-8080]]
org.apache.catalina.LifecycleException: Failed to start component [Connector[HTTP/1.1-8080]]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:153) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.catalina.core.StandardService.addConnector(StandardService.java:239) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.addPreviouslyRemovedConnectors(TomcatEmbeddedServletContainer.java:194) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.start(TomcatEmbeddedServletContainer.java:151) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.startEmbeddedServletContainer(EmbeddedWebApplicationContext.java:293) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.finishRefresh(EmbeddedWebApplicationContext.java:141) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) [spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1191) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1180) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_91]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_91]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_91]
at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-1.3.5.RELEASE.jar:1.3.5.RELEASE]
Caused by: org.apache.catalina.LifecycleException: service.getName(): "Tomcat"; Protocol handler start failed
at org.apache.catalina.connector.Connector.startInternal(Connector.java:993) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:147) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
... 18 common frames omitted
Caused by: java.net.BindException: Address already in use
at sun.nio.ch.Net.bind0(Native Method) ~[na:1.8.0_91]
at sun.nio.ch.Net.bind(Net.java:433) ~[na:1.8.0_91]
at sun.nio.ch.Net.bind(Net.java:425) ~[na:1.8.0_91]
at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:223) ~[na:1.8.0_91]
at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74) ~[na:1.8.0_91]
at org.apache.tomcat.util.net.NioEndpoint.bind(NioEndpoint.java:340) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.tomcat.util.net.AbstractEndpoint.start(AbstractEndpoint.java:773) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.coyote.AbstractProtocol.start(AbstractProtocol.java:473) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
at org.apache.catalina.connector.Connector.startInternal(Connector.java:986) ~[tomcat-embed-core-8.0.33.jar:8.0.33]
... 19 common frames omitted
2016-09-05 09:06:26.743 INFO 1681 --- [ restartedMain] o.apache.catalina.core.StandardService : Stopping service Tomcat
2016-09-05 09:06:26.745 INFO 1681 --- [ost-startStop-1] com.nhncorp.iims2.filter.IIMS2Filter : [IIMS2Filter] destroy()
2016-09-05 09:06:26.745 INFO 1681 --- [ost-startStop-1] c.n.iims2.filter.IIMS2InitialFilter : [IIMS2InitialFilter] destroy()
2016-09-05 09:06:26.764 WARN 1681 --- [ost-startStop-1] o.a.c.loader.WebappClassLoaderBase : The web application [ROOT] appears to have started a thread named [Abandoned connection cleanup thread] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
java.lang.Object.wait(Native Method)
java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:43)
2016-09-05 09:06:26.770 ERROR 1681 --- [ restartedMain] o.s.boot.SpringApplication : Application startup failed
org.springframework.boot.context.embedded.EmbeddedServletContainerException: Unable to start embedded Tomcat servlet container
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.start(TomcatEmbeddedServletContainer.java:165) ~[spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.startEmbeddedServletContainer(EmbeddedWebApplicationContext.java:293) ~[spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.finishRefresh(EmbeddedWebApplicationContext.java:141) ~[spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:541) ~[spring-context-4.2.6.RELEASE.jar:4.2.6.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:118) ~[spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:766) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.createAndRefreshContext(SpringApplication.java:361) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:307) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1191) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1180) [spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_91]
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_91]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_91]
at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_91]
at org.springframework.boot.devtools.restart.RestartLauncher.run(RestartLauncher.java:49) [spring-boot-devtools-1.3.5.RELEASE.jar:1.3.5.RELEASE]
Caused by: java.lang.IllegalStateException: Tomcat connector in failed state
at org.springframework.boot.context.embedded.tomcat.TomcatEmbeddedServletContainer.start(TomcatEmbeddedServletContainer.java:159) ~[spring-boot-1.3.5.RELEASE.jar:1.3.5.RELEASE]
... 15 common frames omitted
上面的一堆异常信息只说明了一件事，8080端口被占用了，应用无法启动。因此需要在终端下查找使用8080端口的进程并将之关闭。
查找端口对应的进程信息的命令有多个，目前我觉的最好用的是lsof命令，查找进程并关闭如下图所示：
解释：lsof全称list open files，在linux/Mac环境下，任何事物都以文件的形式存在，通过文件不仅仅可以访问常规数据，还可以访问网络连接和硬件。所以如传输控制协议 (TCP) 和用户数据报协议 (UDP) 套接字等，系统在后台都为该应用程序分配了一个文件描述符，无论这个文件的本质如何，该文件描述符为应用程序与基础操作系统之间的交互提供了通用接口。因为应用程序打开文件的描述符列表提供了大量关于这个应用程序本身的信息，因此通过lsof工具能够查看这个列表对系统监测以及排错将是很有帮助的。
lsof -i，-i参数是列出所有符合条件的进程。其他lsof命令的相关信息可以参考
http://www.cnblogs.com/peida/archive/2013/02/26/2932972.html。
查找出进程后，如图可以查看进程的相关信息，COMMAND为进程名称，PID为进程ID，FD：文件描述符，应用程序通过文件描述符识别该文件，TYPE：文件类型，DEVICE：指定磁盘的名称，SIZE：文件的大小，NODE：索引节点（文件在磁盘上的标识），NAME：打开文件的确切名称。
根据进程的PID可以使用kill命令将进程干掉，kill -9，-9表示强行杀死进程。在用kill命令杀死进程后，我们可以使用lsof -i:8080重新查找使用8080端口的进程，没找到，说明8080端口进程被杀死，此时，在eclipse中重启Spring Boot的Application就不会出错了。
