请问ext报这个错误是怎么回事

'Ext.JSON.decode(): You're trying to decode an invalid JSON String: <html> <head> <title>Struts Problem Report</title> <style> pre { margin: 0; padding: 0; } </style> </head> <body> <h2>Struts Problem Report</h2> <p> Struts has detected an unhandled exception: </p> <div id="exception-info"> <table> <tr> <td><strong>Messages</strong>:</td> <td> </td> </tr> <tr> <td><strong>File</strong>:</td> <td>com/dxsoft/emr/general/action/LoginAction.java</td> </tr> <tr> <td><strong>Line number</strong>:</td> <td>37</td> </tr> </table> </div> <div id="stacktraces"> <hr /> <h3>Stacktraces</h3> <div class="stacktrace" style="padding-left: 0em"> <strong>java.lang.NullPointerException</strong> <div> <pre> com.dxsoft.emr.general.action.LoginAction.check(LoginAction.java:37) sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) java.lang.reflect.Method.invoke(Method.java:601) com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:441) com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:280) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:243) com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:165) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:252) org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:179) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:94) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:235) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:130) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:138) com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:165) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:179) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176) com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:237) org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52) org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:488) org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77) org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91) org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:242) org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) org.apache.struts2.dispatcher.ActionContextCleanUp.doFilter(ActionContextCleanUp.java:102) org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:242) org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) com.dxsoft.emr.common.filter.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:53) org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:242) org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:243) org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:201) org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:163) org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:108) org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:556) org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118) org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:402) org.apache.coyote.http11.Http11AprProcessor.process(Http11AprProcessor.java:310) org.apache.coyote.http11.Http11AprProtocol$Http11ConnectionHandler.process(Http11AprProtocol.java:575) org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1555) java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) java.lang.Thread.run(Thread.java:722) </pre> </div> </div> </div> <div class="footer"> <hr /> <p> You are seeing this page because development mode is enabled. Development mode, or devMode, enables extra debugging behaviors and reports to assist developers. To disable this mode, set: <pre> struts.devMode=false </pre> in your <code>WEB-INF/classes/struts.properties</code> file. </p> </div> </body> </html> ' when calling method: [nsIDOMEventListener::handleEvent]
[在此错误处中断]  Filtered chrome url chrome://firebug/content/net/spy.js求各位大神指点~~