Struts2的问题 （Struts.xml配置）

Question

我在Struts.xml中不加<constant name="struts.devMode" value="true" /> 时候，就能正常运行！加了后，就出错。控制台的错误提示：到底怎么处理，请大家帮帮忙！！！！！ 信息: Parsing configuration file [struts.xml]
2010-11-22 18:47:40 com.opensymphony.xwork2.util.logging.commons.CommonsLogger info
信息: Overriding property struts.i18n.reload - old value: false new value: true
2010-11-22 18:47:40 com.opensymphony.xwork2.util.logging.commons.CommonsLogger info
信息: Overriding property struts.configuration.xml.reload - old value: false new value: true
2010-11-22 18:47:41 org.apache.catalina.core.StandardContext filterStart
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:275)
at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:397)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:108)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:3696)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:4343)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:791)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:771)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:525)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:920)
at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:883)
at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:492)
at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1138)
at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:311)
at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:117)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1053)
at org.apache.catalina.core.StandardHost.start(StandardHost.java:719)
at org.apache.catalina.core.ContainerBase.start(ContainerBase.java:1045)
at org.apache.catalina.core.StandardEngine.start(StandardEngine.java:443)
at org.apache.catalina.core.StandardService.start(StandardService.java:516)
at org.apache.catalina.core.StandardServer.start(StandardServer.java:710)
at org.apache.catalina.startup.Catalina.start(Catalina.java:566)
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:288)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:413)
2010-11-22 18:47:41 org.apache.catalina.core.StandardContext start
严重: Error filterStart
2010-11-22 18:47:41 org.apache.catalina.core.StandardContext start
严重: Context [/Struts2_Introduction] startup failed due to previous errors
2010-11-22 18:47:42 org.apache.coyote.http11.Http11Protocol start
信息: Starting Coyote HTTP/1.1 on http-9080
2010-11-22 18:47:42 org.apache.jk.common.ChannelSocket init
信息: JK: ajp13 listening on /0.0.0.0:8009
2010-11-22 18:47:42 org.apache.jk.server.JkMain start
信息: Jk running ID=0 time=0/16  config=null
2010-11-22 18:47:42 org.apache.catalina.startup.Catalina start
信息: Server startup in 2788 ms

Answer 1

还有控制台第一句话  
The Apache Tomcat Native library which allows optimal performance in production environments was not found on the java.library.path: C:\Program Files\Java\jdk1.6.0_22\bin;F:\Program Files\Apache Software Foundation\Tomcat 6.0\bin这个not found 为什么还可以正常运行呢 ！（在不加<constant name="struts.devMode" value="true" />的时候）

Answer 2

struts.xml 如下：<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
    "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
    "http://struts.apache.org/dtds/struts-2.0.dtd"><struts>       <constant name="struts.devMode" value="true" />
         <package name="default" namespace="/" extends="struts-default">
        <action name="hello">
            <result >/hello.jsp </result>
        </action>
         <action name="form" class="com.yk.test_action.Formaction" >
            <result name="yk">/success.jsp </result>
        </action>
    </package>
</struts>