解决方法：重启服务器

严重: Servlet.service() for servlet [default] in context with path [] threw exception

java.lang.NullPointerException  at com.opensymphony.xwork2.util.ClassLoaderUtil.getResource(ClassLoaderUtil.java:93)  at com.opensymphony.xwork2.util.location.LocationUtils.getLocation(LocationUtils.java:285)  at com.opensymphony.xwork2.util.location.LocationUtils.getLocation(LocationUtils.java:199)  at com.opensymphony.xwork2.XWorkException.<init>(XWorkException.java:104)  at com.opensymphony.xwork2.XWorkException.<init>(XWorkException.java:87)  at com.opensymphony.xwork2.config.ConfigurationException.<init>(ConfigurationException.java:75)  at org.apache.struts2.config.DefaultPropertiesProvider.register(DefaultPropertiesProvider.java:47)  at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:180)  at com.opensymphony.xwork2.config.ConfigurationManager.conditionalReload(ConfigurationManager.java:271)  at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:72)  at org.apache.struts2.dispatcher.Dispatcher.getContainer(Dispatcher.java:888)  at org.apache.struts2.dispatcher.ng.PrepareOperations.createActionContext(PrepareOperations.java:77)  at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:78)  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)  at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)  at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)  at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)  at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)  at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)  at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)  at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:929)  at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)  at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)  at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1002)  at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:585)  at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1813)  at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)  at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)  at java.lang.Thread.run(Thread.java:722)