Tomcat 7.0 报错 求教?报错

org.apache.catalina.LifecycleException: Failed to start component [StandardEngi
e[Catalina].StandardHost[localhost].StandardContext[/examples]]
        at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:154)
        at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBas
.java:901)
        at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:8
7)
        at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:633


        at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.ja
a:1114)
        at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfi
.java:1672)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:4
1)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
        at java.util.concurrent.FutureTask.run(FutureTask.java:166)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor
java:1110)