multithreading - 线程卡在 UIComponent.popComponentFromEL 处

Question

我的应用程序使用 JSF 2.1 和 PrimeFaces。最近，由于一些线程卡住，观察到 CPU 利用率非常高。所有卡住线程的卡住线程转储都指向 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)

这是怎么造成的，如何解决？

Answer 1

根据 Mojarra issue 2722当您错误地将组件实例绑定(bind)到托管 bean 的 bean 属性(该托管 bean 不在请求范围内，但在更广泛的范围内)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。另请参阅JSF 2.0 specitication第3.1.5章:

3.1.5 Component Bindings

...

Component bindings are often used in conjunction with JavaBeans that are dynamically instantiated via the ManagedBean Creation facility (see Section 5.8.1 “VariableResolver and the Default VariableResolver”). It is stronglyrecommend that application developers place managed beans that are pointed at by component binding expressions in“request” scope. This is because placing it in session or application scope would require thread-safety, sinceUIComponent instances depends on running inside of a single thread. There are also potentially negative impacts onmemory management when placing a component binding in “session” scope.

另请参阅:

• 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?