NAME 在 TreeTableRenderer.encodeEnd

Question

这是我在 xhtml 页面上的 TreeTable 定义：

<p:treeTable var="r" value="#{mybean.tree}">

我可以在 catalina.out 文件中看到这种情况每天都会发生几次：

12-Jan-2015 10:13:00.119 SEVERE [ajp-apr-8009-exec-211] com.sun.faces.application.view.FaceletViewHandlingStrategy.handleRenderException Error Rendering View[/my_page.xhtml]
     java.lang.NullPointerException
        at org.primefaces.component.treetable.TreeTableRenderer.encodeEnd(TreeTableRenderer.java:127)
        at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:919)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1863)
        at com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback.visit(PartialViewContextImpl.java:582)
        at com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback(PartialVisitContext.java:183)
        at org.primefaces.component.api.UITree.visitTree(UITree.java:648)
        at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
        at javax.faces.component.UIForm.visitTree(UIForm.java:371)
        at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
        at com.sun.faces.context.PartialViewContextImpl.processComponents(PartialViewContextImpl.java:403)
        at com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:322)
        at org.primefaces.context.PrimePartialViewContext.processPartial(PrimePartialViewContext.java:60)
        at javax.faces.component.UIViewRoot.encodeChildren(UIViewRoot.java:1004)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856)
        at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:430)
        at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:133)
        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:219)
        at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
        at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
        at org.apache.coyote.ajp.AbstractAjpProcessor.process(AbstractAjpProcessor.java:831)
        at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
        at org.apache.tomcat.util.net.AprEndpoint$SocketWithOptionsProcessor.run(AprEndpoint.java:2344)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(Thread.java:745)

    12-Jan-2015 10:13:00.120 SEVERE [ajp-apr-8009-exec-211] com.sun.faces.context.AjaxExceptionHandlerImpl.handlePartialResponseError java.lang.NullPointerException
        at org.primefaces.component.treetable.TreeTableRenderer.encodeEnd(TreeTableRenderer.java:127)
        at javax.faces.component.UIComponentBase.encodeEnd(UIComponentBase.java:919)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1863)
        at com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback.visit(PartialViewContextImpl.java:582)
        at com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback(PartialVisitContext.java:183)
        at org.primefaces.component.api.UITree.visitTree(UITree.java:648)
        at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
        at javax.faces.component.UIForm.visitTree(UIForm.java:371)
        at javax.faces.component.UIComponent.visitTree(UIComponent.java:1700)
        at com.sun.faces.context.PartialViewContextImpl.processComponents(PartialViewContextImpl.java:403)
        at com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:322)
        at org.primefaces.context.PrimePartialViewContext.processPartial(PrimePartialViewContext.java:60)
        at javax.faces.component.UIViewRoot.encodeChildren(UIViewRoot.java:1004)
        at javax.faces.component.UIComponent.encodeAll(UIComponent.java:1856)
        at com.sun.faces.application.view.FaceletViewHandlingStrategy.renderView(FaceletViewHandlingStrategy.java:430)
        at com.sun.faces.application.view.MultiViewHandler.renderView(MultiViewHandler.java:133)
        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:219)
        at javax.faces.webapp.FacesServlet.service(FacesServlet.java:647)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:291)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
        at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:239)
        at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
        at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
        at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
        at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501)
        at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:142)
        at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
        at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
        at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
        at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:537)
        at org.apache.coyote.ajp.AbstractAjpProcessor.process(AbstractAjpProcessor.java:831)
        at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:658)
        at org.apache.tomcat.util.net.AprEndpoint$SocketWithOptionsProcessor.run(AprEndpoint.java:2344)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(Thread.java:745)

我没有收到任何用户投诉，也不确定发生这种情况时用户在做什么。我以为她只是打开页面，但因为 handlePartialResponseError 我猜它也可能是 expanding/collapsing.

错误是否表明我的对象在树的一个条目中是 null？在我的代码中，我确保没有添加任何空值，所以不应该是这种情况。

mybean 是 @SessionScoped @ManagedBean（以前是 @ViewScoped 但现在为每个用户缓存树）。

我的设置是：

Tomcat 8.0.15
Mojarra 2.2.8
Primefaces 5.1
RHEL 7.0

Answer 1

正如@BalusC 在他的评论中所写，当 UI 树正在构建时更改后端树时会发生此异常。

当 p:treeTable 构建时，它会调用 getTree() 方法很多次，每个类别至少调用一次。如果其中一个调用接收到一个 TreeNode 对象，该对象不等于其他调用，则将抛出此异常。

在我的代码中，我确保 getTree() 将始终 return 相同的 TreeNode 对象，如果它是在不到 10 毫秒前由同一用户最后一次调用的。那修好了。

更好的解决方案是在 PrimeFaces 中进行修复，使 p:treeTable 仅请求 TreeNode 对象一次。

Answer 2

我认为这不是一个好的解决方案。代码应该更像这样：

public TreeNode getRoot() {
    checkSession();
    if (root == null) {
        root = new DefaultTreeNode(data, null);
    }
    return root;   
 }

确保它是同一个对象（假定 bean 的正确范围）

迈克尔

Answer 3

调用 <p:ajax event="select" onstart="func()" /> 的以下 JS 函数 onstart。

function func(){
    var originalVal = $('<YOUR_TREETABLE_ID>_selection').val();
    var arr = originalVal.split(',');
    $('<YOUR_TREETABLE_ID>_selection').val(arr[arr.length-1]);
}

NAME 在 TreeTableRenderer.encodeEnd

NPE at TreeTableRenderer.encodeEnd

primefaces

jsf-2.2