今天看到以下异常，昨天还好好的，今天怎么就不行了呢，有点纳闷，仔细查看了提示，找到了问题出现的原因。

严重: ContainerBase.addChild: start: 
org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/Product]]
	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:632)
	at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1229)
	at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1875)
	at java.util.concurrent.Executors$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$Worker.run(ThreadPoolExecutor.java:615)
	at java.lang.Thread.run(Thread.java:744)
Caused by: java.lang.IllegalArgumentException: Invalid <url-pattern> myAcount in servlet mapping
	at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:3279)
	at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:3254)
	at org.apache.catalina.deploy.WebXml.configureContext(WebXml.java:1361)
	at org.apache.catalina.startup.ContextConfig.webConfig(ContextConfig.java:1341)
	at org.apache.catalina.startup.ContextConfig.configureStart(ContextConfig.java:873)
	at org.apache.catalina.startup.ContextConfig.lifecycleEvent(ContextConfig.java:371)
	at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
	at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)
	at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5355)
	at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
	... 10 more
四月 17, 2018 7:55:43 上午 org.apache.catalina.startup.HostConfig deployDirectory
严重: Error deploying web application directory H:\apache-tomcat-7.0.52-windows-x64\apache-tomcat-7.0.52\webapps\Product
java.lang.IllegalStateException: ContainerBase.addChild: start: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/Product]]
	at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:904)
	at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
	at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:632)
	at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1229)
	at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1875)
	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)

可以看到的是

Caused by: java.lang.IllegalArgumentException: Invalid <url-pattern> myAcount in servlet mapping
	at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:3279)
	at org.apache.catalina.core.StandardContext.addServletMapping(StandardContext.java:3254)
	at org.apache.catalina.deploy.WebXml.configureContext(WebXml.java:1361)

myAccout是我新建的一个Servelet的mapping，然后就以下什么都明白了。就是写mapping的时候忘记了在前面添加"/"号。。呃。。。这错误有点低级
希望能给大家解决问题提供些帮助吧，别被这些小错误给困扰到！嘻嘻