War file cannot be opened by Tomcat

Hi all,

I generated a war package with War plugin,but this package cannot be opened by Tomcat,following is the exception :信息: Deploying web application archive xxxxxxxxx.war 2014-5-8 16:36:28 org.apache.catalina.core.ContainerBase addChildInternal 严重: ContainerBase.addChild: start: LifecycleException: Error initializaing : java.lang.NullPointerException

at org.apache.catalina.core.StandardContext.start(StandardContext.java:4 088)

at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase .java:791)

at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:77 1)

at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:525)

at org.apache.catalina.startup.HostConfig.deployWAR(HostConfig.java:830)

at org.apache.catalina.startup.HostConfig.deployWARs(HostConfig.java:719 )

at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:490 )

at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1217)

at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java :293)

at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(Lifecycl eSupport.java:117)

at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBas e.java:1337)

at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.p rocessChildren(ContainerBase.java:1601)

at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.p rocessChildren(ContainerBase.java:1610)

at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.r un(ContainerBase.java:1590)

at java.lang.Thread.run(Thread.java:662)

But I put all files of the war under a folder of webapps of Tomcat,Tomcat can run the web app normally,I don’t know why,pls help me ,thank you very much!

sorry,version of Gradle is 1.12