我为我的页面编写了一个webdriver测试，它测试了一个primefaces向导组件和行为。有一次，我收到了这个错误：
java.lang.NullPointerException
at org.primefaces.component.wizard.WizardRenderer.encodeStep(WizardRenderer.java:77)
at org.primefaces.component.wizard.WizardRenderer.encodeEnd(WizardRenderer.java:59)
at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:875)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1786)
at com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback.visit(PartialViewContextImpl.java:517)
at com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback(PartialVisitContext.java:183)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1612)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
at javax.faces.component.UIForm.visitTree(UIForm.java:362)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
at com.sun.faces.context.PartialViewContextImpl.processComponents(PartialViewContextImpl.java:378)
at com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:298)
at javax.faces.context.PartialViewContextWrapper.processPartial(PartialViewContextWrapper.java:183)
at javax.faces.context.PartialViewContextWrapper.processPartial(PartialViewContextWrapper.java:183)
at javax.faces.context.PartialViewContextWrapper.processPartial(PartialViewContextWrapper.java:183)
at javax.faces.component.UIViewRoot.encodeChildren(UIViewRoot.java:982)
at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1779)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:411)
at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:124)
at javax.faces.application.ViewHandlerWrapper.renderView(ViewHandlerWrapper.java:286)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:120)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:594)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at com.meinanliegen.handlers.filters.NoCacheFilter.doFilter(NoCacheFilter.java:42)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:79)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.omnifaces.filter.FacesExceptionFilter.doFilter(FacesExceptionFilter.java:56)
at org.omnifaces.filter.HttpFilter.doFilter(HttpFilter.java:75)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.omnifaces.filter.GzipResponseFilter.doFilter(GzipResponseFilter.java:148)
at org.omnifaces.filter.HttpFilter.doFilter(HttpFilter.java:75)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.omnifaces.filter.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:115)
at org.omnifaces.filter.HttpFilter.doFilter(HttpFilter.java:75)
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:225)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
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:999)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565)
at org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:1812)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:722)
我的primefaces向导看起来像：
<ui:composition xmlns="http://www.w3.org/1999/xhtml" xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html" xmlns:ui="http://java.sun.com/jsf/facelets"
xmlns:p="http://primefaces.org/ui">
<p:growl id="growl" autoUpdate="true" life="6000" showDetail="true" />
<h:form prependId="false" style="height : 100%" id="registrationFormWizardId">
<f:view beforePhase="#{userRegistrationWizard.afterPhase}">
</f:view>
<p:panel id="registrationFormWizardPanelGrid">
<p:panelGrid>
<p:row>
<p:column>
<p:wizard widgetVar="wiz" flowListener="#{userRegistrationWizard.onFlowProcess}"
step="#{userRegistrationWizard.step}" backLabel="Zurück" nextLabel="Weiter">
<p:tab id="idOne" title="TITLE1">
<ui:include src="/WEB-INF/templates/steps/registration_step1.xhtml"></ui:include>
</p:tab>
<p:tab id="idTwo" title="TITLE2">
<ui:include src="/WEB-INF/templates/steps/registration_step2.xhtml"></ui:include>
</p:tab>
<p:tab id="idThree" title="TITLE3">
<ui:include src="/WEB-INF/templates/steps/registration_step3.xhtml"></ui:include>
</p:tab>
</p:wizard>
</p:column>
</p:row>
</p:panelGrid>
</p:panel>
</h:form>
有人知道为什么会抛出这个异常吗？
更新：
我使用的是Primefaces 3.5和MyFaces 2.1.17
答案 0 :(得分：3)
根据WizardRenderer的Java代码，在向导中找不到应该呈现的选项卡。如果您的测试以某种方式返回到第一页或最后一页的下一页，这可能会产生影响。