java - IBM JSF PortletSession 为空

Question

我们将 IBM WebSphere Portal 与 JSF 结合使用。 可怕的组合，一次又一次地证明它的可怕。

最近我们遇到了一个问题，我们有一个带有 链接 到 下载 servlet 的 portlet(包含在 same war 中) .此 servlet 尝试从 HttpSession 读取某些属性，这些属性应该由 portlet 在 <APPLICATION_SCOPE 中的 em>PortletSession。

但有时，servlet 无法读取 HttpSession 中的任何所需属性。这是我进行调查的原因。经过一番搜索后，我发现它只发生在 portlet 被第一次加载(没有任何页面重新加载)。

经过一些实验后，我在 PortletSession 上调用 getAttributeNames(scope) 时得到了一个 NullPointerException。 PortletSession 是通过faces 上下文 从外部上下文 获得的。我发现 PortletSession 实际上是一个 com.ibm.faces.portlet.httpbridge.PortletSessionWrapper 显然 应该包含 实际的 PortletSession。此包含的 session 显然是空。 PortletSessionWrapper 的大多数方法通过空检查来防止 NPE，但是，getAttributeNames(scope) 没有(如果你问我)。

现在是个大问题:为什么 上的(真实的)PortletSession null portlet 的首次加载 ?

提供包装器的 jsf-protletbrdige 的 META-INF:

Manifest-Version: 1.0
Ant-Version: Apache Ant 1.7.1
Created-By: IBM Corporation
Specification-Title: Java Server Faces
Implementation-Title: JSF Widget Library (JWL) - Portlet Bridge
Implementation-Version: JWL v3_1_5
Implementation-Vendor: IBM
Build-Version: 20100212_0941
Build-Date: February 12 2010
Copyright-Info: Copyright (c) 2003,2008, International Business Machines Corporation. All Rights Reserved.

调用 getAttributeNames(scope) 方法时的堆栈跟踪:

[21-8-12 17:52:16:051 CEST] 00000041 servlet       E com.ibm.ws.webcontainer.servlet.ServletWrapper service SRVE0068E: Uncaught exception created in one of the service methods of the servlet Header in application PA_mytestportlet. Exception created : javax.servlet.ServletException: javax.portlet.PortletException: /MyPortletView.jsp(105,9) '#{MyPortletView.productId}' Error reading 'productId' on type mytest.portal.testportlet.view.MyPortletViewBean
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServlet.doDispatch(PortletServlet.java:361)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServletCollaboratorChainImpl.doCollaborator(PortletServletCollaboratorChainImpl.java:82)
    at com.ibm.isclite.container.collaborator.PortletServletCollaborator.doDispatch(PortletServletCollaborator.java:143)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServletCollaboratorChainImpl.doCollaborator(PortletServletCollaboratorChainImpl.java:74)
    at com.ibm.ws.portletcontainer.rrd.RRDServerPortletServletCollaborator.doDispatch(RRDServerPortletServletCollaborator.java:60)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServletCollaboratorChainImpl.doCollaborator(PortletServletCollaboratorChainImpl.java:74)
    at com.ibm.ws.portletcontainer.cache.CacheCollaborator.doDispatch(CacheCollaborator.java:74)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServletCollaboratorChainImpl.doCollaborator(PortletServletCollaboratorChainImpl.java:74)
    at com.ibm.wps.pe.pc.waspc.core.impl.PortletServletCollaboratorImpl.doDispatch(PortletServletCollaboratorImpl.java:121)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServletCollaboratorChainImpl.doCollaborator(PortletServletCollaboratorChainImpl.java:74)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServlet.dispatch(PortletServlet.java:208)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServlet.service(PortletServlet.java:165)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:831)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1657)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1597)
    at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:104)
    at com.ibm.ws.webcontainer.filter.WebAppFilterChain._doFilter(WebAppFilterChain.java:77)
    at com.ibm.ws.webcontainer.filter.WebAppFilterManager.doFilter(WebAppFilterManager.java:908)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:934)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:502)
    at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.handleRequest(ServletWrapperImpl.java:179)
    at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java:121)
    at com.ibm.ws.portletcontainer.webextension.PortletExtensionProcessor.handleRequest(PortletExtensionProcessor.java:86)
    at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.include(WebAppRequestDispatcher.java:686)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletInvokerImpl.invoke(PortletInvokerImpl.java:214)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletInvokerCollaboratorChainImpl.doCollaborator(PortletInvokerCollaboratorChainImpl.java:78)
    at com.ibm.ws.portletcontainer.cache.PortletInvokerCacheCollaborator.doRender(PortletInvokerCacheCollaborator.java:58)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletInvokerCollaboratorChainImpl.doCollaborator(PortletInvokerCollaboratorChainImpl.java:67)
    at com.ibm.ws.portletcontainer.ext.PortletInvokerPerformanceCollaborator.invoke(PortletInvokerPerformanceCollaborator.java:313)
    at com.ibm.ws.portletcontainer.ext.PortletInvokerPerformanceCollaborator.doInvoke(PortletInvokerPerformanceCollaborator.java:101)
    at com.ibm.ws.portletcontainer.ext.PortletInvokerPerformanceCollaborator.invokePMI(PortletInvokerPerformanceCollaborator.java:163)
    at com.ibm.ws.portletcontainer.ext.PortletInvokerPerformanceCollaborator.doInvoke(PortletInvokerPerformanceCollaborator.java:91)
    at com.ibm.ws.portletcontainer.ext.PortletInvokerPerformanceCollaborator.doRender(PortletInvokerPerformanceCollaborator.java:74)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletInvokerCollaboratorChainImpl.doCollaborator(PortletInvokerCollaboratorChainImpl.java:67)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletInvokerImpl.render(PortletInvokerImpl.java:97)
    at com.ibm.ws.portletcontainer.PortletContainerImpl.doRender(PortletContainerImpl.java:121)
    at com.ibm.ws.portletcontainer.PortletContainerInvokerCollaboratorChainImpl.doCollaborator(PortletContainerInvokerCollaboratorChainImpl.java:80)
    at com.ibm.ws.portletcontainer.ext.ExtCollaborator.doRender(ExtCollaborator.java:74)
    at com.ibm.ws.portletcontainer.PortletContainerInvokerCollaboratorChainImpl.doCollaborator(PortletContainerInvokerCollaboratorChainImpl.java:67)
    at com.ibm.ws.portletcontainer.cache.CacheInvokerCollaborator.doRender(CacheInvokerCollaborator.java:66)
    at com.ibm.ws.portletcontainer.PortletContainerInvokerCollaboratorChainImpl.doCollaborator(PortletContainerInvokerCollaboratorChainImpl.java:67)
    at com.ibm.ws.portletcontainer.PortletContainerImpl.renderPortlet(PortletContainerImpl.java:91)
    at com.ibm.ws.portletcontainer.pcinvoker.PortletInvokerImpl$2.run(PortletInvokerImpl.java:100)
    at java.security.AccessController.doPrivileged(AccessController.java:251)
    at com.ibm.ws.portletcontainer.pcinvoker.PortletInvokerImpl.invokeRender(PortletInvokerImpl.java:96)
    at com.ibm.wps.pe.pc.waspc.core.impl.PortletInvokerImpl$1.invoke(PortletInvokerImpl.java:98)
    at com.ibm.wps.pe.pc.waspc.core.impl.PortletInvokerImpl.invoke(PortletInvokerImpl.java:181)
    at com.ibm.wps.pe.pc.waspc.core.impl.PortletInvokerImpl.invokeRender(PortletInvokerImpl.java:96)
    at com.ibm.wps.pe.pc.waspc.PortletContainerImpl.renderPortlet(PortletContainerImpl.java:116)
    at com.ibm.wps.pe.pc.PortletContainerImpl.doRenderPortlet(PortletContainerImpl.java:641)
    at com.ibm.wps.pe.ext.render.AbstractRenderManager.performService(AbstractRenderManager.java:264)
    at com.ibm.wps.pe.pc.PortletContainerImpl.renderPortlet(PortletContainerImpl.java:132)
    at com.ibm.wps.engine.tags.PortletRenderTag.doStartTag(PortletRenderTag.java:179)
    at com.ibm._jsp._Control._jspx_meth_portal$1skin_portletRender_0(_Control.java:276)
    at com.ibm._jsp._Control._jspx_meth_portal$1logic_if_1(_Control.java:315)
    at com.ibm._jsp._Control._jspService(_Control.java:168)
    at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:99)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:831)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1657)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:939)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:502)
    at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.handleRequest(ServletWrapperImpl.java:179)
    at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java:121)
    at com.ibm.ws.jsp.webcontainerext.AbstractJSPExtensionServletWrapper.handleRequest(AbstractJSPExtensionServletWrapper.java:259)
    at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.include(WebAppRequestDispatcher.java:686)
    at com.ibm.wps.services.dispatcher.DispatcherServiceImpl.handleRequest(DispatcherServiceImpl.java:93)
    at com.ibm.wps.services.dispatcher.DispatcherServiceImpl.include(DispatcherServiceImpl.java:53)
    at com.ibm.wps.services.dispatcher.Dispatcher.include(Dispatcher.java:50)
    at com.ibm.wps.engine.templates.skins.Default.render(Default.java:154)
    at com.ibm.wps.engine.templates.SkinTemplate.render(SkinTemplate.java:68)
    at com.ibm.wps.composition.elements.Component.render(Component.java:638)
    at com.ibm.wps.composition.elements.Control.render(Control.java:159)
    at com.ibm.wps.composition.Composition.render(Composition.java:3102)
    at com.ibm.wps.composition.Composition.render(Composition.java:163)
    at com.ibm.websphere.personalization.transformation.PznTransformationLayoutModel.render(PznTransformationLayoutModel.java:90)
    at com.ibm.wps.model.wrappers.LayoutModelWrapperFactoryImpl$LayoutModelWrapperImpl.render(LayoutModelWrapperFactoryImpl.java:275)
    at com.ibm.wps.model.ModelUtil$WrappedCompositionModel.render(ModelUtil.java:1124)
    at com.ibm._jsp._UnlayeredContainer_2D_H._jspService(_UnlayeredContainer_2D_H.java:224)
    at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:99)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:831)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1657)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:939)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:502)
    at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.handleRequest(ServletWrapperImpl.java:179)
    at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java:121)
    at com.ibm.ws.jsp.webcontainerext.AbstractJSPExtensionServletWrapper.handleRequest(AbstractJSPExtensionServletWrapper.java:259)
    at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.include(WebAppRequestDispatcher.java:686)
    at com.ibm.wps.services.dispatcher.DispatcherServiceImpl.handleRequest(DispatcherServiceImpl.java:93)
    at com.ibm.wps.services.dispatcher.DispatcherServiceImpl.include(DispatcherServiceImpl.java:53)
    at com.ibm.wps.services.dispatcher.Dispatcher.include(Dispatcher.java:50)
    at com.ibm.wps.engine.templates.skins.Default.render(Default.java:154)
    at com.ibm.wps.engine.templates.SkinTemplate.render(SkinTemplate.java:68)
    at com.ibm.wps.composition.elements.Component.render(Component.java:638)
    at com.ibm.wps.composition.Composition.render(Composition.java:3102)
    at com.ibm.wps.composition.Composition.render(Composition.java:163)
    at com.ibm.websphere.personalization.transformation.PznTransformationLayoutModel.render(PznTransformationLayoutModel.java:90)
    at com.ibm.wps.model.wrappers.LayoutModelWrapperFactoryImpl$LayoutModelWrapperImpl.render(LayoutModelWrapperFactoryImpl.java:275)
    at com.ibm.wps.model.ModelUtil$WrappedCompositionModel.render(ModelUtil.java:1124)
    at com.ibm._jsp._UnlayeredContainer_2D_V._jspService(_UnlayeredContainer_2D_V.java:215)
    at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:99)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:831)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1657)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:939)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:502)
    at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.handleRequest(ServletWrapperImpl.java:179)
    at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java:121)
    at com.ibm.ws.jsp.webcontainerext.AbstractJSPExtensionServletWrapper.handleRequest(AbstractJSPExtensionServletWrapper.java:259)
    at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.include(WebAppRequestDispatcher.java:686)
    at com.ibm.wps.services.dispatcher.DispatcherServiceImpl.handleRequest(DispatcherServiceImpl.java:93)
    at com.ibm.wps.services.dispatcher.DispatcherServiceImpl.include(DispatcherServiceImpl.java:53)
    at com.ibm.wps.services.dispatcher.Dispatcher.include(Dispatcher.java:50)
    at com.ibm.wps.engine.templates.skins.Default.render(Default.java:154)
    at com.ibm.wps.engine.templates.SkinTemplate.render(SkinTemplate.java:68)
    at com.ibm.wps.composition.elements.Component.render(Component.java:638)
    at com.ibm.wps.composition.Composition.render(Composition.java:3102)
    at com.ibm.wps.composition.Composition.render(Composition.java:163)
    at com.ibm.websphere.personalization.transformation.PznTransformationLayoutModel.render(PznTransformationLayoutModel.java:90)
    at com.ibm.wps.model.wrappers.LayoutModelWrapperFactoryImpl$LayoutModelWrapperImpl.render(LayoutModelWrapperFactoryImpl.java:275)
    at com.ibm.wps.engine.tags2.PageRenderTag.doStartTag(PageRenderTag.java:534)
    at com.ibm._jsp._Home._jspService(_Home.java:104)
    at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:99)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:831)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1657)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:939)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:502)
    at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.handleRequest(ServletWrapperImpl.java:179)
    at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java:121)
    at com.ibm.ws.jsp.webcontainerext.AbstractJSPExtensionServletWrapper.handleRequest(AbstractJSPExtensionServletWrapper.java:259)
    at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.include(WebAppRequestDispatcher.java:686)
    at com.ibm.wps.services.dispatcher.DispatcherServiceImpl.handleRequest(DispatcherServiceImpl.java:93)
    at com.ibm.wps.services.dispatcher.DispatcherServiceImpl.include(DispatcherServiceImpl.java:53)
    at com.ibm.wps.services.dispatcher.Dispatcher.include(Dispatcher.java:50)
    at com.ibm.wps.engine.templates.screens.Default.render(Default.java:133)
    at com.ibm.wps.engine.templates.ScreenTemplate.render(ScreenTemplate.java:59)
    at com.ibm.wps.engine.tags2.ScreenRenderTag.doStartTag(ScreenRenderTag.java:182)
    at com.ibm._jsp._Default._jspx_meth_portal$1core_screenRender_0(_Default.java:3623)
    at com.ibm._jsp._Default._jspService(_Default.java:1966)
    at com.ibm.ws.jsp.runtime.HttpJspBase.service(HttpJspBase.java:99)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:831)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1657)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:939)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.handleRequest(ServletWrapper.java:502)
    at com.ibm.ws.webcontainer.servlet.ServletWrapperImpl.handleRequest(ServletWrapperImpl.java:179)
    at com.ibm.wsspi.webcontainer.servlet.GenericServletWrapper.handleRequest(GenericServletWrapper.java:121)
    at com.ibm.ws.jsp.webcontainerext.AbstractJSPExtensionServletWrapper.handleRequest(AbstractJSPExtensionServletWrapper.java:259)
    at com.ibm.ws.webcontainer.webapp.WebAppRequestDispatcher.include(WebAppRequestDispatcher.java:686)
    at com.ibm.wps.services.dispatcher.DispatcherServiceImpl.handleRequest(DispatcherServiceImpl.java:93)
    at com.ibm.wps.services.dispatcher.DispatcherServiceImpl.include(DispatcherServiceImpl.java:53)
    at com.ibm.wps.services.dispatcher.Dispatcher.include(Dispatcher.java:50)
    at com.ibm.wps.engine.templates.themes.Default.doDispatch(Default.java:294)
    at com.ibm.wps.engine.templates.themes.Default.render(Default.java:247)
    at com.ibm.wps.engine.templates.ThemeTemplate.render(ThemeTemplate.java:65)
    at com.ibm.wps.engine.phases.WPRenderPhase.processRendering(WPRenderPhase.java:509)
    at com.ibm.wps.engine.phases.WPBaseRenderPhase.execute(WPBaseRenderPhase.java:194)
    at com.ibm.wps.state.phases.AbstractRenderPhase.next(AbstractRenderPhase.java:106)
    at com.ibm.wps.engine.phases.WPAbstractRenderPhase.next(WPAbstractRenderPhase.java:97)
    at com.ibm.wps.engine.Servlet.callPortal(Servlet.java:860)
    at com.ibm.wps.engine.Servlet.doGet(Servlet.java:617)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:718)
    at com.ibm.wps.engine.Servlet.doFilter(Servlet.java:1257)
    at com.ibm.wps.resolver.servlet.ContentHandlerCleanup.doFilter(ContentHandlerCleanup.java:648)
    at com.ibm.wps.resolver.servlet.AbstractFilter.doFilter(AbstractFilter.java:93)
    at com.ibm.wps.engine.Servlet.service(Servlet.java:1248)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1657)
    at com.ibm.ws.webcontainer.servlet.ServletWrapper.service(ServletWrapper.java:1597)
    at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:131)
    at com.ibm.wps.engine.ExtendedLocaleFilter.doFilter(ExtendedLocaleFilter.java:113)
    at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:188)
    at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:116)
    at com.ibm.wps.resolver.friendly.servlet.FriendlySelectionFilter.doFilter(FriendlySelectionFilter.java:191)
    at com.ibm.ws.webcontainer.filter.FilterInstanceWrapper.doFilter(FilterInstanceWrapper.java:188)
    at com.ibm.ws.webcontainer.filter.WebAppFilterChain.doFilter(WebAppFilterChain.java:116)
    at com.ibm.wps.mappingurl.impl.URLAnalyzer.doFilter(URLAnalyzer.java:381)
 . . .
Caused by: javax.portlet.PortletException: /MyPortletView.jsp(105,9) '#{MyPortletView.productId}' Error reading 'productId' on type mytest.portal.testportlet.view.MyPortletViewBean
    at com.ibm.faces.portlet.FacesPortlet.doRender(FacesPortlet.java:384)
    at com.ibm.faces.portlet.FacesPortlet.doView(FacesPortlet.java:413)
    at com.ibm.faces.portlet.FacesPortlet.doDispatch(FacesPortlet.java:301)
    at javax.portlet.GenericPortlet.render(GenericPortlet.java:233)
    at mytest.portal.testportlet.portlet.HeaderPortlet.render(HeaderPortlet.java:44)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletFilterChainImpl.doFilter(PortletFilterChainImpl.java:128)
    at com.ibm.wps.propertybroker.standard.filter.C2APortletFilter.doFilter(C2APortletFilter.java:183)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletFilterChainImpl.doFilter(PortletFilterChainImpl.java:120)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServlet.doDispatch(PortletServlet.java:573)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServletCollaboratorChainImpl.doCollaborator(PortletServletCollaboratorChainImpl.java:114)
    at com.ibm.isclite.container.collaborator.PortletServletCollaborator.doRender(PortletServletCollaborator.java:71)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServletCollaboratorChainImpl.doCollaborator(PortletServletCollaboratorChainImpl.java:105)
    at com.ibm.ws.portletcontainer.rrd.RRDServerPortletServletCollaborator.doRender(RRDServerPortletServletCollaborator.java:123)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServletCollaboratorChainImpl.doCollaborator(PortletServletCollaboratorChainImpl.java:105)
    at com.ibm.ws.portletcontainer.cache.CacheCollaborator.doRender(CacheCollaborator.java:92)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServletCollaboratorChainImpl.doCollaborator(PortletServletCollaboratorChainImpl.java:105)
    at com.ibm.wps.pe.pc.waspc.core.impl.PortletServletCollaboratorImpl.doRender(PortletServletCollaboratorImpl.java:156)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServletCollaboratorChainImpl.doCollaborator(PortletServletCollaboratorChainImpl.java:105)
    at com.ibm.ws.portletcontainer.invoker.impl.PortletServlet.doDispatch(PortletServlet.java:273)
    ... 203 more
Caused by: org.apache.jasper.el.JspELException: /MyPortletView.jsp(105,9) '#{MyPortletView.productId}' Error reading 'productId' on type mytest.portal.testportlet.view.MyPortletViewBean
    at org.apache.jasper.el.JspValueExpression.getValue(JspValueExpression.java:106)
    at javax.faces.component.UIParameter.getValue(UIParameter.java:167)
    at com.sun.faces.renderkit.html_basic.HtmlBasicRenderer.getParamList(HtmlBasicRenderer.java:518)
    at com.sun.faces.renderkit.html_basic.OutputLinkRenderer.renderAsActive(OutputLinkRenderer.java:203)
    at com.sun.faces.renderkit.html_basic.OutputLinkRenderer.encodeBegin(OutputLinkRenderer.java:100)
    at com.ibm.faces.renderkit.DefaultAjaxRenderer.encodeBegin(DefaultAjaxRenderer.java:64)
    at javax.faces.component.UIComponentBase.encodeBegin(UIComponentBase.java:812)
    at mytest.jsf.util.ChildRendererUtil.renderChildren(ChildRendererUtil.java:45)
    at mytest.portal.ui.jsf.custom.component.htmltag.HtmlTagRenderer.encodeChildren(HtmlTagRenderer.java:110)
    at com.ibm.faces.renderkit.DefaultAjaxRenderer.encodeChildren(DefaultAjaxRenderer.java:73)
    at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:836)
    at mytest.jsf.util.ChildRendererUtil.renderChildren(ChildRendererUtil.java:47)
    at mytest.portal.ui.jsf.custom.component.htmltag.HtmlTagRenderer.encodeChildren(HtmlTagRenderer.java:110)
    at com.ibm.faces.renderkit.DefaultAjaxRenderer.encodeChildren(DefaultAjaxRenderer.java:73)
    at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:836)
    at mytest.jsf.util.ChildRendererUtil.renderChildren(ChildRendererUtil.java:47)
    at mytest.portal.ui.jsf.custom.component.htmltag.HtmlTagRenderer.encodeChildren(HtmlTagRenderer.java:110)
    at com.ibm.faces.renderkit.DefaultAjaxRenderer.encodeChildren(DefaultAjaxRenderer.java:73)
    at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:836)
    at mytest.jsf.util.ChildRendererUtil.renderChildren(ChildRendererUtil.java:47)
    at mytest.portal.ui.jsf.custom.component.htmltag.HtmlTagRenderer.encodeChildren(HtmlTagRenderer.java:110)
    at com.ibm.faces.renderkit.DefaultAjaxRenderer.encodeChildren(DefaultAjaxRenderer.java:73)
    at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:836)
    at mytest.jsf.util.ChildRendererUtil.renderChildren(ChildRendererUtil.java:47)
    at mytest.portal.ui.jsf.custom.component.htmltag.HtmlTagRenderer.encodeChildren(HtmlTagRenderer.java:110)
    at com.ibm.faces.renderkit.DefaultAjaxRenderer.encodeChildren(DefaultAjaxRenderer.java:73)
    at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:836)
    at mytest.jsf.util.ChildRendererUtil.renderChildren(ChildRendererUtil.java:47)
    at mytest.portal.ui.jsf.custom.component.htmltag.HtmlTagRenderer.encodeChildren(HtmlTagRenderer.java:110)
    at com.ibm.faces.renderkit.DefaultAjaxRenderer.encodeChildren(DefaultAjaxRenderer.java:73)
    at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:836)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:936)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:942)
    at javax.faces.render.Renderer.encodeChildren(Renderer.java:148)
    at com.ibm.faces.renderkit.DefaultAjaxRenderer.encodeChildren(DefaultAjaxRenderer.java:73)
    at javax.faces.component.UIComponentBase.encodeChildren(UIComponentBase.java:836)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:936)
    at javax.faces.component.UIComponent.encodeAll(UIComponent.java:942)
    at com.sun.faces.application.ViewHandlerImpl.doRenderView(ViewHandlerImpl.java:292)
    at com.sun.faces.application.ViewHandlerImpl.renderView(ViewHandlerImpl.java:223)
    at com.ibm.faces.portlet.PortletViewHandlerImpl.renderView(PortletViewHandlerImpl.java:79)
    at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:114)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:100)
    at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
    at com.ibm.faces.portlet.FacesPortlet.doRender(FacesPortlet.java:372)
    ... 221 more
Caused by: java.lang.NullPointerException
    at com.ibm.faces.portlet.httpbridge.PortletSessionWrapper.getAttributeNames(PortletSessionWrapper.java:185)
    at mytest.portal.testportlet.view.MyPortletViewBean.getProductId(MyPortletViewBean.java:394)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:60)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:37)
    at java.lang.reflect.Method.invoke(Method.java:611)
    at javax.el.BeanELResolver.getValue(BeanELResolver.java:64)
    at javax.el.CompositeELResolver.getValue(CompositeELResolver.java:143)
    at com.sun.faces.el.FacesCompositeELResolver.getValue(FacesCompositeELResolver.java:73)
    at org.apache.el.parser.AstValue.getValue(AstValue.java:102)
    at org.apache.el.ValueExpressionImpl.getValue(ValueExpressionImpl.java:263)
    at org.apache.jasper.el.JspValueExpression.getValue(JspValueExpression.java:100)
    ... 265 more

session 范围是使用以下代码获取的:

FacesContext facesContext = getFacesContext();
if (facesContext != null) {
    return (PortletSession) facesContext.getExternalContext().getSession(createIfNotExist);
 }
 return null;

createIfNotExist 为 false。

Answer 1

听起来像是 jsf-portletbridge.jar PortletRequestWrapper 类型中的缺陷。 JSF 引用实现被写入 servlet 规范。请求包装器实现了 HttpServletRequest。 ExternalContext.getSession(boolean)将调用 HttpServletRequest.getSession(boolean) .这将返回一个装饰器对象 PortletSessionWrapper，它实现了 HttpSession 和 PortletSession。听起来请求装饰器返回一个 session 装饰器，即使底层 PortletSession 为 null。

我会尝试这种形式的代码:

    PortletRequest request = (PortletRequest) FacesContext.getCurrentInstance()
                                                          .getExternalContext()
                                                          .getRequest();
    PortletSession session = request.getPortletSession(false);
    if (session == null) {
        return null;
    }
    else {
        return session.getAttribute("foo", PortletSession.APPLICATION_SCOPE);
    }