卡在 UIComponent.popComponentFromEL 的线程

Question

我的应用程序使用带有 PrimeFaces 的 JSF 2.1。最近，由于一些卡住的线程，观察到非常高的 CPU 使用率。所有卡住线程的卡住线程转储指向javax.faces.component.UIComponent.popComponentFromEL，如下所示：

javax.faces.component.UIComponent.popComponentFromEL(UIComponent.java:1934)
javax.faces.component.UIComponent.visitTree(UIComponent.java:1633)
javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
org.primefaces.component.api.UIData.visitRows(UIData.java:741)
org.primefaces.component.api.UIData.visitTree(UIData.java:656)
javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
org.primefaces.component.accordionpanel.AccordionPanel.visitTree(AccordionPanel.java:371)
javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
javax.faces.component.UIForm.visitTree(UIForm.java:371)
javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
javax.faces.component.UIComponent.visitTree(UIComponent.java:1623)
com.sun.faces.application.view.StateManagementStrategyImpl.findComponent(StateManagementStrategyImpl.java:440)
com.sun.faces.application.view.StateManagementStrategyImpl.restoreDynamicRemove(StateManagementStrategyImpl.java:412)
com.sun.faces.application.view.StateManagementStrategyImpl.restoreDynamicActions(StateManagementStrategyImpl.java:317)
com.sun.faces.application.view.StateManagementStrategyImpl.restoreView(StateManagementStrategyImpl.java:281)
com.sun.faces.application.StateManagerImpl.restoreView(StateManagerImpl.java:188)
com.sun.faces.application.view.ViewHandlingStrategy.restoreView(ViewHandlingStrategy.java:123)
com.sun.faces.application.view.FaceletViewHandlingStrategy.restoreView(FaceletViewHandlingStrategy.java:453)
com.sun.faces.application.view.MultiViewHandler.restoreView(MultiViewHandler.java:142)
com.sun.faces.lifecycle.RestoreViewPhase.execute(RestoreViewPhase.java:192)
com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
com.sun.faces.lifecycle.RestoreViewPhase.doPhase(RestoreViewPhase.java:116)
com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:227)
weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:125)
weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:300)
weblogic.servlet.internal.TailFilter.doFilter(TailFilter.java:26)
weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
org.primefaces.webapp.filter.FileUploadFilter.doFilter(FileUploadFilter.java:77)
weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
com.ultimatix.bgc.framework.GBGCSessionControllerFilter.doFilter(GBGCSessionControllerFilter.java:90)
weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
com.ultimatix.framework.jsf.util.ForcedLoginFilter.doFilter(ForcedLoginFilter.java:505)
weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
com.ultimatix.framework.jsf.util.IndexFilter.doFilter(IndexFilter.java:338)
weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
com.ultimatix.framework.jsf.util.SecurityInterceptor.doFilter(SecurityInterceptor.java:40)
weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
weblogic.servlet.internal.RequestEventsFilter.doFilter(RequestEventsFilter.java:27)
weblogic.servlet.internal.FilterChainImpl.doFilter(FilterChainImpl.java:56)
weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3715)
weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3681)
weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:321)
weblogic.security.service.SecurityManager.runAs(SecurityManager.java:120)
weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2277)
weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2183)
weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1454)
weblogic.work.ExecuteThread.execute(ExecuteThread.java:207)
weblogic.work.ExecuteThread.run(ExecuteThread.java:176)

这是怎么引起的，我该如何解决？

Answer 1

根据 Mojarra issue 2722，当您错误地将组件实例绑定到不受请求范围但在更广泛范围内的托管 bean 的 bean 属性时，就会发生这种情况。

<x:someComponent binding="#{viewOrSessionOrApplicationScopedBean.component}" />

相应地修复代码，使这种情况永远不会发生。组件本质上是请求范围的，绝对不能在多个请求之间共享。另见JSF 2.0 specitication 第 3.1.5 章：

3.1.5 组件绑定

...

组件绑定通常与通过 Managed 动态实例化的 JavaBean 结合使用 Bean 创建工具（请参见第 5.8.1 节“VariableResolver 和默认的 VariableResolver”）。 强烈 建议应用程序开发人员将组件绑定表达式指向的托管 bean 放在 “请求”范围。 这是因为将其置于会话或应用程序范围内需要线程安全，因为 UIComponent 实例依赖于在单个线程内运行。也有潜在的负面影响 将组件绑定放在“会话”范围内时的内存管理。

另见：

• How does the 'binding' attribute work in JSF? When and how should it be used?
• What is component binding in JSF? When it is preferred to be used?