启动Java Web项目时提示错误：Servlet mapping specifies an unknown servlet name Action
完整错误信息如下：
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[/testcs_dn-admin-web]] at java.util.concurrent.FutureTask.report(Unknown Source) at java.util.concurrent.FutureTask.get(Unknown Source) at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123) at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:799) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/testcs_dn-admin-web]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154) ... 6 more Caused by: java.lang.IllegalArgumentException: Servlet mapping specifies an unknown servlet name Action at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:3275) at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:3254) at org.apache.catalina.deploy.WebXml.configureContext(WebXml.java:1430) at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1344) at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:876) at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:374) at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117) at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5355) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ... 6 more 十二月 09, 2014 2:21:25 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(Unknown Source) at java.util.concurrent.FutureTask.get(Unknown Source) at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1123) at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:300) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.StandardService.startInternal(StandardService.java:443) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:731) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.startup.Catalina.start(Catalina.java:689) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:321) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:455) Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549) at java.util.concurrent.FutureTask.run(Unknown Source) at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) at java.lang.Thread.run(Unknown Source) Caused by: org.apache.catalina.LifecycleException: A child container failed during start at org.apache.catalina.core.ContainerBase.startInternal(ContainerBase.java:1131) at org.apache.catalina.core.StandardHost.startInternal(StandardHost.java:799) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ... 6 more 十二月 09, 2014 2:21:25 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[8006]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154) at org.apache.catalina.startup.Catalina.start(Catalina.java:689) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) at java.lang.reflect.Method.invoke(Unknown Source) at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:321) at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:455) Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardService[Catalina]] at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154) at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:731) 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:154) at org.apache.catalina.core.StandardService.startInternal(StandardService.java:443) 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:1131) at org.apache.catalina.core.StandardEngine.startInternal(StandardEngine.java:300) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) ... 11 more 十二月 09, 2014 2:21:25 下午 org.apache.coyote.AbstractProtocol pause 信息: Pausing ProtocolHandler ["http-bio-8081"] 十二月 09, 2014 2:21:25 下午 org.apache.coyote.AbstractProtocol pause 信息: Pausing ProtocolHandler ["ajp-bio-8010"] 十二月 09, 2014 2:21:25 下午 org.apache.catalina.core.StandardService stopInternal 信息: Stopping service Catalina 十二月 09, 2014 2:21:25 下午 org.apache.coyote.AbstractProtocol destroy 信息: Destroying ProtocolHandler ["http-bio-8081"] 十二月 09, 2014 2:21:25 下午 org.apache.coyote.AbstractProtocol destroy 信息: Destroying ProtocolHandler ["ajp-bio-8010"]最初这个问题是以： A child container failed during start 来记录的，但是 有很多问题会导致 A child container failed during start 错误，而在这个错误之上，还会有其它的错误，比如本错误：
Caused by: java.lang.IllegalArgumentException: Servlet mapping specifies an unknown servlet name Action
问题的产生：
我是 Copy 的其它项目的 web.xml 文件，里面有配置的 Servlet 本项目中没有，就导致了这个错误。
解决方法：解决这个问题的关键在于错误信息中的：
打开项目下的“src\main\webapp\WEB-INF\web.xml”文件，查找类似下面的节点：将这个节点删除，问题就解决了。
