严重: Exception starting filter struts2

异常情况如下:

—、

严重: Exception starting filter struts2
java.lang.NullPointerException
 at com.opensymphony.xwork2.util.FileManager$FileRevision.needsReloading(FileManager.java:209)
 at com.opensymphony.xwork2.util.FileManager.fileNeedsReloading(FileManager.java:60)
 at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.needsReload(XmlConfigurationProvider.java:325)
 at org.apache.struts2.config.StrutsXmlConfigurationProvider.needsReload(StrutsXmlConfigurationProvider.java:168)
 at com.opensymphony.xwork2.config.ConfigurationManager.conditionalReload(ConfigurationManager.java:220)
 at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:61)
 at org.apache.struts2.dispatcher.Dispatcher.getContainer(Dispatcher.java:774)
 at org.apache.struts2.dispatcher.ng.InitOperations.initStaticContentLoader(InitOperations.java:77)
 at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:49)
 at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:295)
 at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:422)
 at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:115)
 at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4072)
 at org.apache.catalina.core.StandardContext.start(StandardContext.java:4726)
 at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:799)
 at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:779)
 at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:601)
 at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1079)
 at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:1002)
 at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:506)
 at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1317)
 at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:324)
 at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:142)
 at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1065)
 at org.apache.catalina.core.StandardHost.start(StandardHost.java:840)
 at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1057)
 at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:463)
 at org.apache.catalina.core.StandardService.start(StandardService.java:525)
 at org.apache.catalina.core.StandardServer.start(StandardServer.java:754)
 at org.apache.catalina.startup.Catalina.start(Catalina.java:595)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:597)
 at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:289)
 at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:414)
2012-7-25 8:36:41 org.apache.catalina.core.StandardContext start
严重: Error filterStart
2012-7-25 8:36:41 org.apache.catalina.core.StandardContext start
严重: Context [/HouseRent_001_login] startup failed due to previous errors
2012-7-25 8:36:41 org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
严重: The web application [/HouseRent_001_login] created a ThreadLocal with key of type [com.opensymphony.xwork2.inject.ContainerImpl$10] (value [com.opensymphony.xwork2.inject.ContainerImpl$10@95215b]) and a value of type [java.lang.Object[]] (value [[Ljava.lang.Object;@c10de0]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.
2012-7-25 8:36:41 org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap
严重: The web application [/HouseRent_001_login] created a ThreadLocal with key of type [com.opensymphony.xwork2.inject.ContainerImpl$10] (value [com.opensymphony.xwork2.inject.ContainerImpl$10@75f5b7]) and a value of type [java.lang.Object[]] (value [[Ljava.lang.Object;@56fc16]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.
2012-7-25 8:36:41 org.apache.coyote.http11.Http11Protocol start
信息: Starting Coyote HTTP/1.1 on http-6666
2012-7-25 8:36:42 org.apache.jk.common.ChannelSocket init
信息: JK: ajp13 listening on /0.0.0.0:8009
2012-7-25 8:36:42 org.apache.jk.server.JkMain start
信息: Jk running ID=0 time=0/31  config=null
2012-7-25 8:36:42 org.apache.catalina.startup.Catalina start
信息: Server startup in 3886 ms

 二、web配置如下

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
 http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
 <welcome-file-list>
  <welcome-file>index.jsp</welcome-file>
 </welcome-file-list>
 <filter>
  <filter-name>struts2</filter-name>
  <filter-class>
   org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter
  </filter-class>
 </filter>

 <filter-mapping>
  <filter-name>struts2</filter-name>
  <url-pattern>/*</url-pattern>
 </filter-mapping>
</web-app>

求解决。。。