部署Struts2.x时报Exception starting filter struts2 java.lang.NullPointerException
最近开始看Struts2，之前在项目中用过Struts1.x
1和2的差别还是有点
但这些都是其次的
最开始的配置一个简单的Hello World就把我丢翻了
到最后改了之后才觉得这个问题真变态，虽然这个问题在网上的解决方案已经说了无数次了
哎
如果你用Tomcat部署的时候遇到这样的问题，
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.FilterDispatcher.init(FilterDispatcher.java:191) 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:3709) at org.apache.catalina.core.StandardContext.start(StandardContext.java:4363) 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:926) at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:889) at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:492) at org.apache.catalina.startup.HostConfig.start(HostConfig.java:1149) 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:578) 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)
?那么恭喜你也许我说的方案能解决你的问题了
干掉你的Tomcat安装路径中的所有空格包括版本号前的空格（默认安装那有空格，我浪费了很多时间就是在那个空格上面）
至于原因还有待研究，该休息了，明天继续学习
