错误日志：
严重: A child container failed during start java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[]] at java.util.concurrent.FutureTask.report(FutureTask.java:122) at java.util.concurrent.FutureTask.get(FutureTask.java:192) at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:939) at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:872) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1419) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1409) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745) Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167) ... 6 more Caused by: java.lang.IllegalArgumentException: The servlets named [cn.baum.upload.FileUploadServlet] and [cn.baum.upload.FileUploadServlet2] are both mapped to the url-pattern [/fileUpload] which is not permitted at org.apache.tomcat.util.descriptor.web.WebXml.addServletMappingDecoded(WebXml.java:326) at org.apache.tomcat.util.descriptor.web.WebXml.addServletMapping(WebXml.java:319) at org.apache.catalina.startup.ContextConfig.processAnnotationWebServlet(ContextConfig.java:2388) at org.apache.catalina.startup.ContextConfig.processAnnotationsStream(ContextConfig.java:2065) at org.apache.catalina.startup.ContextConfig.processAnnotationsWebResource(ContextConfig.java:1951) at org.apache.catalina.startup.ContextConfig.processAnnotationsWebResource(ContextConfig.java:1945) at org.apache.catalina.startup.ContextConfig.processAnnotationsWebResource(ContextConfig.java:1945) at org.apache.catalina.startup.ContextConfig.processAnnotationsWebResource(ContextConfig.java:1945) at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1152) at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:774) at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:299) at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:94) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5113) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ... 6 more 十月 26, 2018 5:43:13 下午 org.apache.catalina.core.ContainerBase startInternal 严重: A child container failed during start java.util.concurrent.ExecutionException: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]] at java.util.concurrent.FutureTask.report(FutureTask.java:122) at java.util.concurrent.FutureTask.get(FutureTask.java:192) at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:939) at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.StandardService.startInternal(StandardService.java:422) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:793) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.startup.Catalina.start(Catalina.java:681) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:353) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:493) Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1419) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1409) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) at java.lang.Thread.run(Thread.java:745) Caused by: org.apache.catalina.LifecycleException: A child container failed during start at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:948) at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:872) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ... 6 more 十月 26, 2018 5:43:13 下午 org.apache.catalina.startup.Catalina start 严重: The required Server component failed to start so Tomcat is unable to start. org.apache.catalina.LifecycleException: Failed to start component [StandardServer[8005]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167) at org.apache.catalina.startup.Catalina.start(Catalina.java:681) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:353) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:493) Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardService[Catalina]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167) at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:793) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ... 7 more Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167) at org.apache.catalina.core.StandardService.startInternal(StandardService.java:422) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ... 9 more Caused by: org.apache.catalina.LifecycleException: A child container failed during start at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:948) at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:262) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ... 11 more
错误日志中标红的信息是造成启动失败的原因，原因是我在同一个项目copy一个FileUploadServlet文件时，忘了修改@WebServlet("/fileUpload")的路径或注释起来，造成两个Servlet文都映射到了同一个路径中，所以启动Tomcat失败。
同理如果不是用@WebServlet注解来映射路径的话，如果在web.xml中配置了相同的url-pattern路径，也会造成Tomcat启动失败，一个意思。