Invalid select.do in servlet mapping

org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/emp]]
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
	at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
	at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
	at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:649)
	at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1247)
	at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1898)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
	at java.util.concurrent.FutureTask.run(FutureTask.java:262)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.IllegalArgumentException: Invalid  select.do in servlet mapping
	at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:3298)
	at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:3273)
	at org.apache.catalina.deploy.WebXml.configureContext(WebXml.java:1438)
	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:5378)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
	... 10 more

上述原因是因为servlet的名字不合法导致的，名字必须以/开始！否则启动的时候就会报错！访问项目的任何资源都会404！