我正试图在表上进行数据搜索。我试着按照展示中DataTable过滤器的素数面的例子进行操作。然而，奇怪的是，当我输入要查找的值时，表中的内容会立即清空。例如，我想找到用户名"A"，然后当我键入"A"时，表的内容将消失。这是我的桌子：
<h:form id="dataTable">
<p:dataTable var="users" rows="10" value="#{listUserAccountBean.users}"
style="width: 100%; float: left; margin-top:10px;" paginator="true"
pageLinks="10" rowsPerPageTemplate="5,10,15"
widgetVar="widgetWorkOrder" rowIndexVar="rowIndex"
paginatorPosition="bottom" emptyMessage="No record found"
styleClass="no-dtbl-header" id="listDataUser" filteredValue="#{listUserAccountBean.filteredUsers}"
paginatorTemplate="{CurrentPageReport} {FirstPageLink} {PreviousPageLink} {PageLinks} {NextPageLink} {LastPageLink} {RowsPerPageDropdown}">
<f:facet name="header">
<p:outputPanel>
<h:outputText value="Search all fields:" />
<p:inputText id="globalFilter" onkeyup="PF('widgetWorkOrder').filter()" placeholder="Enter keyword"/>
</p:outputPanel>
</f:facet>
<p:columnGroup type="header">
<p:column headerText="Username" />
<p:column headerText="Password" />
<p:column headerText="Action" colspan="2"/>
</p:columnGroup>
<p:column filterBy="#{users.username}" footerText="test1" filterMatchMode="test1">
<h:outputText value="#{users.username}" />
</p:column>
<p:column filterBy="#{users.password}" footerText="test2" filterMatchMode="test2">
<h:outputText value="#{users.password}" />
</p:column>
<p:column style="text-align: center">
<p:commandLink action="#{listUserAccountBean.goToEditUserAccount(users)}">
<p:graphicImage name="edit.png" library="images" width="25px"
height="25px" />
</p:commandLink>
</p:column>
<p:column style="text-align: center">
<p:commandLink actionListener="#{listUserAccountBean.prepareDelete(users)}"
oncomplete="PF('dlg-delete').show();">
<p:graphicImage name="delete-admin.png" library="images"
width="25px" height="25px" />
</p:commandLink>
</p:column>
</p:dataTable>
</h:form>
这是我的日志猫：
14:37:38,073 INFO [javax.enterprise.resource.webcontainer.jsf.context] (http-localhost-127.0.0.1-8081-2) java.lang.ClassCastException: org.primefaces.component.column.Column cannot be cast to org.primefaces.component.row.Row: java.lang.ClassCastException: org.primefaces.component.column.Column cannot be cast to org.primefaces.component.row.Row
at org.primefaces.component.datatable.feature.FilterFeature.populateFilterMetaDataInColumnGroup(FilterFeature.java:283) [primefaces-5.3.jar:5.3]
at org.primefaces.component.datatable.feature.FilterFeature.populateFilterMetaData(FilterFeature.java:257) [primefaces-5.3.jar:5.3]
at org.primefaces.component.datatable.feature.FilterFeature.decode(FilterFeature.java:90) [primefaces-5.3.jar:5.3]
at org.primefaces.component.datatable.DataTable.processValidators(DataTable.java:716) [primefaces-5.3.jar:5.3]
at com.sun.faces.context.PartialViewContextImpl$PhaseAwareVisitCallback.visit(PartialViewContextImpl.java:508) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.component.visit.PartialVisitContext.invokeVisitCallback(PartialVisitContext.java:183) [jsf-impl-2.1.7-jbossorg-2.jar:]
at org.primefaces.component.api.UIData.visitTree(UIData.java:822) [primefaces-5.3.jar:5.3]
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
at javax.faces.component.UIForm.visitTree(UIForm.java:371) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
at javax.faces.component.UIComponent.visitTree(UIComponent.java:1623) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
at com.sun.faces.context.PartialViewContextImpl.processComponents(PartialViewContextImpl.java:376) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.context.PartialViewContextImpl.processPartial(PartialViewContextImpl.java:252) [jsf-impl-2.1.7-jbossorg-2.jar:]
at org.primefaces.context.PrimePartialViewContext.processPartial(PrimePartialViewContext.java:60) [primefaces-5.3.jar:5.3]
at javax.faces.component.UIViewRoot.processValidators(UIViewRoot.java:1170) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
at com.sun.faces.lifecycle.ProcessValidationsPhase.execute(ProcessValidationsPhase.java:76) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101) [jsf-impl-2.1.7-jbossorg-2.jar:]
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118) [jsf-impl-2.1.7-jbossorg-2.jar:]
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593) [jboss-jsf-api_2.1_spec-2.0.1.Final.jar:2.0.1.Final]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:329) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) [jbossweb-7.0.13.Final.jar:]
at org.apache.logging.log4j.web.Log4jServletFilter.doFilter(Log4jServletFilter.java:67) [log4j-web-2.0.2.jar:2.0.2]
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:280) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:248) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:275) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) [jbossweb-7.0.13.Final.jar:]
at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:153) [jboss-as-web-7.1.1.Final.jar:7.1.1.Final]
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.13.Final.jar:]
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) [jbossweb-7.0.13.Final.jar:]
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [jbossweb-7.0.13.Final.jar:]
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:671) [jbossweb-7.0.13.Final.jar:]
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930) [jbossweb-7.0.13.Final.jar:]
at java.lang.Thread.run(Thread.java:722) [rt.jar:1.7.0_21]
14:37:38,020 SEVERE [javax.enterprise.resource.webcontainer.jsf.context] (http-localhost-127.0.0.1-8081-2) java.lang.NullPointerException
我错过什么了吗？
添加一个p:row作为包装p:column的p:columnGroup的子级。
<p:columnGroup type="header">
<p:row>
<p:column headerText="Username" />
<p:column headerText="Password" />
<p:column headerText="Action" colspan="2"/>
</p:row>
</p:columnGroup>
PrimeFaces代码似乎搜索了columnGroup的第一个子级，并试图将其强制转换为column。