Question

我有这个错误：

jan 03,2014 6:43:56 PM com.sun.faces.context.PartialViewContextImpl processPartial INFO：java.lang.ClassCastException： javax.faces.event.ValueChangeEvent无法强制转换为 javax.faces.event.AjaxBehaviorEvent java.lang.ClassCastException： javax.faces.event.ValueChangeEvent无法强制转换为 javax.faces.event.AjaxBehaviorEvent

xhtml中的树：

                <p:tree id="catTree"
                        value="#{listCatsRenderer.categoryTree}" var="ndt"
                        selectionMode="single" 
                        selection="#{listCatsRenderer.selectedNode}"
                        draggable="true"
                        droppable="true"
                        animate="true" styleClass="tree_general"
                        propagateSelectionUp="false"
                        dynamic="true"
                        >

                    <p:ajax event="dragdrop" listener="#{listCatsRenderer.onDragDrop}" update=":main:catTree"/>

                    <p:treeNode>
                        <p:inplace event="dblclick" editor="true" >
                            <h:inputText value="#{ndt.name}"/>
                        </p:inplace>
                    </p:treeNode>  
                </p:tree>

从bean加载：

@Named
@SessionScoped
public class ListCatsRenderer extends ARenderer implements Serializable {
.
.
.
@Override
public TreeNode getCategoryTree() {
    if (categoryTree == null) {
        updateCategoryTree(); //DBS load
    } 
    return categoryTree;
}

在任何dragdrop事件之后它会抛出异常。当我转向上面的条件时，它可以正常工作。知道为什么吗？谢谢。

// EDIT 过程事件的代码，但是它永远不会到达那里

public void onDragDrop(TreeDragDropEvent event) {
    System.out.println("dragged: " + event.getDragNode());
    System.out.println("dropped: " + event.getDropNode() + " > " + event.getDropIndex());
}

完整的堆栈跟踪可能有所帮助：

jan 05,2014 11:50:28 AM com.sun.faces.lifecycle.ProcessValidationsPhase执行警告： java.lang.ClassCastException：javax.faces.event.ValueChangeEvent 无法转换为javax.faces.event.AjaxBehaviorEvent javax.faces.FacesException：java.lang.ClassCastException： javax.faces.event.ValueChangeEvent无法强制转换为 javax.faces.event.AjaxBehaviorEvent at com.sun.faces.context.PartialViewContextImpl.processPartial（PartialViewContextImpl.java:270）在 org.primefaces.context.PrimePartialViewContext.processPartial（PrimePartialViewContext.java:57）在 javax.faces.component.UIViewRoot.processValidators（UIViewRoot.java:1193）在 com.sun.faces.lifecycle.ProcessValidationsPhase.execute（ProcessValidationsPhase.java:76）在com.sun.faces.lifecycle.Phase.doPhase（Phase.java:101）at com.sun.faces.lifecycle.LifecycleImpl.execute（LifecycleImpl.java:198）在javax.faces.webapp.FacesServlet.service（FacesServlet.java:646）at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:305）在 org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:210）在 org.jboss.weld.servlet.ConversationFilter.doFilter（ConversationFilter.java:66）在 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:243）在 org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:210）在 org.apache.catalina.filters.SetCharacterEncodingFilter.doFilter（SetCharacterEncodingFilter.java:108）在 org.apache.catalina.core.ApplicationFilterChain.internalDoFilter（ApplicationFilterChain.java:243）在 org.apache.catalina.core.ApplicationFilterChain.doFilter（ApplicationFilterChain.java:210）在 org.apache.catalina.core.StandardWrapperValve.invoke（StandardWrapperValve.java:222）在 org.apache.catalina.core.StandardContextValve.invoke（StandardContextValve.java:123）在 org.apache.catalina.authenticator.AuthenticatorBase.invoke（AuthenticatorBase.java:472）在 org.apache.catalina.core.StandardHostValve.invoke（StandardHostValve.java:171）在 org.apache.catalina.valves.ErrorReportValve.invoke（ErrorReportValve.java:99）在 org.apache.catalina.valves.AccessLogValve.invoke（AccessLogValve.java:936）在 org.apache.catalina.core.StandardEngineValve.invoke（StandardEngineValve.java:118）在 org.apache.catalina.connector.CoyoteAdapter.service（CoyoteAdapter.java:407）在 org.apache.coyote.http11.AbstractHttp11Processor.process（AbstractHttp11Processor.java:1004）在 org.apache.coyote.AbstractProtocol $ AbstractConnectionHandler.process（AbstractProtocol.java:589）在 org.apache.tomcat.util.net.JIoEndpoint $ SocketProcessor.run（JIoEndpoint.java:310）在 java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1145）在 java.util.concurrent.ThreadPoolExecutor中的$ Worker.run（ThreadPoolExecutor.java:615）在java.lang.Thread.run（Thread.java:724）引起： java.lang.ClassCastException：javax.faces.event.ValueChangeEvent 无法转换为javax.faces.event.AjaxBehaviorEvent at org.primefaces.component.tree.Tree.queueEvent（Tree.java:308）at at javax.faces.component.UIComponentBase.queueEvent（UIComponentBase.java:1057）在 javax.faces.component.UIComponentBase.queueEvent（UIComponentBase.java:1057）在 javax.faces.component.UIComponentBase.queueEvent（UIComponentBase.java:1057）在javax.faces.component.UIInput.validate（UIInput.java:992）at javax.faces.component.UIInput.executeValidate（UIInput.java:1249）at at javax.faces.component.UIInput.processValidators（UIInput.java:712）at at javax.faces.component.UIComponentBase.processValidators（UIComponentBase.java:1261）在 org.primefaces.component.inplace.Inplace.processValidators（Inplace.java:218）在 org.primefaces.component.api.UITree.processColumnChildren（UITree.java:442）在org.primefaces.component.api.UITree.processNode（UITree.java:372）在org.primefaces.component.api.UITree.processNode（UITree.java:380）在org.primefaces.component.api.UITree.processNodes（UITree.java:365）在 org.primefaces.component.api.UITree.processValidators（UITree.java:308）在 org.primefaces.component.tree.Tree.processValidators（Tree.java:377）在 com.sun.faces.context.PartialViewContextImpl $ PhaseAwareVisitCallback.visit（PartialViewContextImpl.java:552）在 com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback（PartialVisitContext.java:183）在org.primefaces.component.api.UITree.visitTree（UITree.java:552）at javax.faces.component.UIComponent.visitTree（UIComponent.java:1700）at at javax.faces.component.UIComponent.visitTree（UIComponent.java:1700）at at javax.faces.component.UIForm.visitTree（UIForm.java:371）at javax.faces.component.UIComponent.visitTree（UIComponent.java:1700）at at javax.faces.component.UIComponent.visitTree（UIComponent.java:1700）at at com.sun.faces.context.PartialViewContextImpl.processComponents（PartialViewContextImpl.java:399）在 com.sun.faces.context.PartialViewContextImpl.processPartial（PartialViewContextImpl.java:263） ...... 28

Answer 1

适用于Mojarra 2.0.3（FCS b03），PrimeFaces 4.0。

请告诉我们您使用的版本的更多信息，并提供您的支持bean的onDragDrop方法的确切代码。我猜这与你的方法没有使用正确的参数类型有关（ TreeDragDropEvent 是预期的，而不是 ValueChangeEvent ）。

应该是这样的：

public void onDragDrop(TreeDragDropEvent event) { 
  ...
}

primefaces tree drag，drop ajax event

1 个答案: