通过任何类型的验证，我突然得到了这个异常。
java.lang.NullPointerException
at com.opensymphony.xwork2.validator.AnnotationValidationConfigurationBuilder.processCustomValidatorAnnotation(AnnotationValidationConfigurationBuilder.java:393)
at com.opensymphony.xwork2.validator.AnnotationValidationConfigurationBuilder.processValidationAnnotation(AnnotationValidationConfigurationBuilder.java:233)
at com.opensymphony.xwork2.validator.AnnotationValidationConfigurationBuilder.processAnnotations(AnnotationValidationConfigurationBuilder.java:74)
at com.opensymphony.xwork2.validator.AnnotationValidationConfigurationBuilder.buildAnnotationClassValidatorConfigs(AnnotationValidationConfigurationBuilder.java:772)
at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.buildClassValidatorConfigs(AnnotationActionValidatorManager.java:254)
at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.buildValidatorConfigs(AnnotationActionValidatorManager.java:342)
at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.buildValidatorConfigs(AnnotationActionValidatorManager.java:321)
at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.getValidators(AnnotationActionValidatorManager.java:86)
at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.validate(AnnotationActionValidatorManager.java:125)
at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.validate(AnnotationActionValidatorManager.java:117)
at com.opensymphony.xwork2.validator.AnnotationActionValidatorManager.validate(AnnotationActionValidatorManager.java:112)
at com.opensymphony.xwork2.validator.ValidationInterceptor.doBeforeInvocation(ValidationInterceptor.java:222)
at com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:263)
at org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:211)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:211)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:190)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at org.apache.struts2.interceptor.MultiselectInterceptor.intercept(MultiselectInterceptor.java:75)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:90)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:243)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:256)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:145)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:171)
at com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:98)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:176)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:187)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at de.trackstone.interceptors.BasicLoginInterceptor.intercept(BasicLoginInterceptor.java:49)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at de.trackstone.interceptors.BasicLoginInterceptor.intercept(BasicLoginInterceptor.java:49)
at com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:249)
at org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:54)
at org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:510)
at org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:91)
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:240)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:164)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:462)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:164)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:562)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:395)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:250)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:188)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:302)
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)
一切都很好，但今天早上停止工作。
我清理、刷新并从 tomcat 中删除了该项目，但似乎没有任何效果。编辑：我发现这个：
Unable to load config class org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor at interceptor - jar:file:/home/suad/Desktop/MyProject/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp1/wtpwebapps/My/WEB-INF/lib/struts2-core-2.3.1.jar!/struts-default.xml:148:127 probably due to a missing jar, which might be fine if you never plan to use the validation interceptor
Actual exception
Caught Exception while registering Interceptor class org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor - interceptor - jar:file:/home/suad/Desktop/MyProject/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp1/wtpwebapps/My/WEB-INF/lib/struts2-core-2.3.1.jar!/struts-default.xml:148:127
at org.apache.struts2.impl.StrutsObjectFactory.buildInterceptor(StrutsObjectFactory.java:77)
at com.opensymphony.xwork2.config.providers.InterceptorBuilder.constructInterceptorReference(InterceptorBuilder.java:70)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.lookupInterceptorReference(XmlConfigurationProvider.java:1035)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadInterceptorStack(XmlConfigurationProvider.java:852)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadInterceptorStacks(XmlConfigurationProvider.java:865)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadInterceptors(XmlConfigurationProvider.java:888)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.addPackage(XmlConfigurationProvider.java:468)
at com.opensymphony.xwork2.config.providers.XmlConfigurationProvider.loadPackages(XmlConfigurationProvider.java:278)
at org.apache.struts2.config.StrutsXmlConfigurationProvider.loadPackages(StrutsXmlConfigurationProvider.java:112)
at com.opensymphony.xwork2.config.impl.DefaultConfiguration.reloadContainer(DefaultConfiguration.java:204)
at com.opensymphony.xwork2.config.ConfigurationManager.getConfiguration(ConfigurationManager.java:66)
at org.apache.struts2.dispatcher.Dispatcher.init_PreloadConfiguration(Dispatcher.java:390)
at org.apache.struts2.dispatcher.Dispatcher.init(Dispatcher.java:436)
at org.apache.struts2.dispatcher.ng.InitOperations.initDispatcher(InitOperations.java:69)
at org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.init(StrutsPrepareAndExecuteFilter.java:51)
at org.apache.catalina.core.ApplicationFilterConfig.initFilter(ApplicationFilterConfig.java:273)
at org.apache.catalina.core.ApplicationFilterConfig.getFilter(ApplicationFilterConfig.java:254)
at org.apache.catalina.core.ApplicationFilterConfig.setFilterDef(ApplicationFilterConfig.java:372)
at org.apache.catalina.core.ApplicationFilterConfig.<init>(ApplicationFilterConfig.java:98)
at org.apache.catalina.core.StandardContext.filterStart(StandardContext.java:4562)
at org.apache.catalina.core.StandardContext$2.call(StandardContext.java:5240)
at org.apache.catalina.core.StandardContext$2.call(StandardContext.java:5235)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
Caused by: Server returned HTTP response code: 403 for URL: http://opensymphony.com/xwork/xwork-validator-config-1.0.dtd - Class: sun.net.www.protocol.http.HttpURLConnection
File: HttpURLConnection.java
Method: getInputStream
Line: 1612 - sun/net/www/protocol/http/HttpURLConnection.java:1612:-1
at com.opensymphony.xwork2.util.DomHelper.parse(DomHelper.java:115)
at com.opensymphony.xwork2.validator.DefaultValidatorFileParser.parseValidatorDefinitions(DefaultValidatorFileParser.java:117)
at com.opensymphony.xwork2.validator.DefaultValidatorFactory.retrieveValidatorConfiguration(DefaultValidatorFactory.java:195)
at com.opensymphony.xwork2.validator.DefaultValidatorFactory.parseValidators(DefaultValidatorFactory.java:184)
at com.opensymphony.xwork2.validator.DefaultValidatorFactory.<init>(DefaultValidatorFactory.java:55)
... 63 more
Caused by: java.io.IOException: Server returned HTTP response code: 403 for URL: http://opensymphony.com/xwork/xwork-validator-config-1.0.dtd
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1612)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.setupCurrentEntity(XMLEntityManager.java:653)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.startEntity(XMLEntityManager.java:1291)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.startDTDEntity(XMLEntityManager.java:1258)
at com.sun.org.apache.xerces.internal.impl.XMLDTDScannerImpl.setInputSource(XMLDTDScannerImpl.java:260)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDriver.dispatch(XMLDocumentScannerImpl.java:1151)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDriver.next(XMLDocumentScannerImpl.java:1047)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:960)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:607)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:116)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:488)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:835)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:123)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1210)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:568)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl.parse(SAXParserImpl.java:302)
at com.opensymphony.xwork2.util.DomHelper.parse(DomHelper.java:113)
... 67 more
Caused by: Server returned HTTP response code: 403 for URL: http://opensymphony.com/xwork/xwork-validator-config-1.0.dtd - Class: sun.net.www.protocol.http.HttpURLConnection
File: HttpURLConnection.java
Method: getInputStream
Line: 1612 - sun/net/www/protocol/http/HttpURLConnection.java:1612:-1
at com.opensymphony.xwork2.util.DomHelper.parse(DomHelper.java:115)
at com.opensymphony.xwork2.validator.DefaultValidatorFileParser.parseValidatorDefinitions(DefaultValidatorFileParser.java:117)
at com.opensymphony.xwork2.validator.DefaultValidatorFactory.retrieveValidatorConfiguration(DefaultValidatorFactory.java:195)
at com.opensymphony.xwork2.validator.DefaultValidatorFactory.parseValidators(DefaultValidatorFactory.java:184)
at com.opensymphony.xwork2.validator.DefaultValidatorFactory.<init>(DefaultValidatorFactory.java:55)
... 63 more
Caused by: java.io.IOException: Server returned HTTP response code: 403 for URL: http://opensymphony.com/xwork/xwork-validator-config-1.0.dtd
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1612)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.setupCurrentEntity(XMLEntityManager.java:653)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.startEntity(XMLEntityManager.java:1291)
at com.sun.org.apache.xerces.internal.impl.XMLEntityManager.startDTDEntity(XMLEntityManager.java:1258)
at com.sun.org.apache.xerces.internal.impl.XMLDTDScannerImpl.setInputSource(XMLDTDScannerImpl.java:260)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDriver.dispatch(XMLDocumentScannerImpl.java:1151)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$DTDDriver.next(XMLDocumentScannerImpl.java:1047)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl$PrologDriver.next(XMLDocumentScannerImpl.java:960)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:607)
at com.sun.org.apache.xerces.internal.impl.XMLNSDocumentScannerImpl.next(XMLNSDocumentScannerImpl.java:116)
at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:488)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:835)
at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:764)
at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:123)
at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1210)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:568)
at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl.parse(SAXParserImpl.java:302)
at com.opensymphony.xwork2.util.DomHelper.parse(DomHelper.java:113)
... 67 more