SpringBoot启动报错：
org.apache.catalina.LifecycleException: Protocol handler start failed
at org.apache.catalina.connector.Connector.startInternal(Connector. ~[tomcat-embed-core-9.0.16.jar:9.0.16]
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase. ~[tomcat-embed-core-9.0.16.jar:9.0.16]
at org.apache.catalina.core.StandardService.addConnector(StandardService. [tomcat-embed-core-9.0.16.jar:9.0.16]
at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.addPreviouslyRemovedConnectors(TomcatWebServer. [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.start(TomcatWebServer. [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.startWebServer(ServletWebServerApplicationContext. [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.finishRefresh(ServletWebServerApplicationContext. [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext. [spring-context-5.1.5.RELEASE.jar:5.1.5.RELEASE]
at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext. [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication. [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication. [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication. [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication. [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication. [spring-boot-2.1.3.RELEASE.jar:2.1.3.RELEASE]
at com.liupei.SysApplication.main(SysApplication. [classes/:na]
Caused by: java.net.BindException: Address already in use: bind
at sun.nio.ch.Net.bind0(Native Method) ~[na:1.8.0_131]
at sun.nio.ch.Net.bind(Net. ~[na:1.8.0_131]
at sun.nio.ch.Net.bind(Net. ~[na:1.8.0_131]
at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl. ~[na:1.8.0_131]
at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor. ~[na:1.8.0_131]
at org.apache.tomcat.util.net.NioEndpoint.initServerSocket(NioEndpoint. ~[tomcat-embed-core-9.0.16.jar:9.0.16]
at org.apache.tomcat.util.net.NioEndpoint.bind(NioEndpoint. ~[tomcat-embed-core-9.0.16.jar:9.0.16]
at org.apache.tomcat.util.net.AbstractEndpoint.bindWithCleanup(AbstractEndpoint. ~[tomcat-embed-core-9.0.16.jar:9.0.16]
at org.apache.tomcat.util.net.AbstractEndpoint.start(AbstractEndpoint. ~[tomcat-embed-core-9.0.16.jar:9.0.16]
at org.apache.coyote.AbstractProtocol.start(AbstractProtocol. ~[tomcat-embed-core-9.0.16.jar:9.0.16]
at org.apache.catalina.connector.Connector.startInternal(Connector. ~[tomcat-embed-core-9.0.16.jar:9.0.16]
... 14 common frames omitted
解决：端口被占用，查找进程
