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首先，代碼：Primefaces的dataTable與複選框問題
<p:dataTable id="tablePriceCriteria" value="#{kuBean.criteriaList}" selection="#{kuBean.selectedCriteriaList}" var="criteria">
<p:column selectionMode="multiple" style="width: 50px;"/>
<p:column>
<f:facet name="header">
<h:outputText value="Criteria name" />
</f:facet>
<h:outputText value="#{criteria.criteriaPK.criteriaName}" />
</p:column>
<p:column>
<f:facet name="header">
<h:outputText value="Measure unit" />
</f:facet>
<h:outputText value="#{criteria.measureUnit}" />
</p:column>
<p:column>
<f:facet name="header">
<h:outputText value="Size" />
</f:facet>
<h:outputText value="#{criteria.criteriaPK.size}" />
</p:column>
<f:facet name="footer">
<p:commandButton value="Add criteria to service" actionListener="#{kuBean.addPricesToService}"
oncomplete="wiz.next()"/>
</f:facet>
</p:dataTable>
</p:panel>
</p:tab>
<p:tab id="Prices" title="Price">
<p:panel>
<p:dataTable value="#{kuBean.service.pricesList}" var="price">
<f:facet name="header">
Usluga: #{kuBean.service.serviceName}
</f:facet>
<p:column headerText="Criteria name">
<f:facet name="output">
<h:outputText value="#{price.criteria.criteriaPK.criteriaName}"/>
</f:facet>
</p:column>
<p:column headerText="Measure unit">
<f:facet name="output">
<h:outputText value="#{price.criteria.measureUnit}"/>
</f:facet>
</p:column>
<p:column headerText="Size">
<f:facet name="output">
<h:outputText value="#{price.criteria.criteriaPK.size}"/>
</f:facet>
</p:column>
<p:column headerText="Service Price">
<p:cellEditor>
<f:facet name="output">
<h:outputText value="#{price.price}"/>
</f:facet>
<f:facet name="input">
<p:inputText value="#{price.price}" style="width: 100%;"/>
</f:facet>
</p:cellEditor>
</p:column>
</p:dataTable>
當我看着代碼，我認識到，有沒有機會有人瞭解任何東西，所以我試圖解釋這裏發生了什麼。
我在數據庫表（主鍵是粗體顯示）：
服務：服務ID，服務名
標準：criteriaName，大小，measureUnit
價格：服務ID，criteriaName ，尺寸，價格
我的課程是：
服務，具有價格清單， 標準，也有價格和持有criteriaName和大小criteriaPK的名單。 價格有獨特的標準和服務。還有pricePK具有標準名稱，大小和serviceID。
我創建了具有屬性widgetVar =「wiz」的primefaces嚮導。最後是一個問題。在dataTable中是所有標準的列表。當我查看一些標準並點擊「向服務添加標準」按鈕時，我想要執行的操作是所選標準添加到服務中。
方法addPricesToService的代碼：
List<Prices> priceList = new LinkedList<Price>();
for (int i = 0; i < getSelectedCriteriaList().length; i++) {
Criteria criteria = getSelectedCriteriaList[i];
Price c = new Price(new PricePK(service.getPriceID(), criteria.getCriteriaPK().getCriteriaName(), criteria.getCriteriaPK().getSize()));
c.setPrice(0);
priceList.add(c);
}
service.setPriceList(priceList);
我所得到的只是一個例外：
SEVERE: Received 'java.lang.NullPointerException' when invoking action listener '#{kuBean.dodajCeneUsluzi}' for component 'j_idt46'
SEVERE: java.lang.NullPointerException
at util.ServiceCreatingManager.addPricesToService(ServiceCreatingManager.java:166)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.el.parser.AstValue.invoke(AstValue.java:234)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297)
at javax.faces.event.MethodExpressionActionListener.processAction(MethodExpressionActionListener.java:153)
at javax.faces.event.ActionEvent.processListener(ActionEvent.java:88)
at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:772)
at javax.faces.component.UICommand.broadcast(UICommand.java:300)
at javax.faces.component.UIData.broadcast(UIData.java:912)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:775)
at javax.faces.component.UIViewRoot.processDecodes(UIViewRoot.java:943)
at com.sun.faces.lifecycle.ApplyRequestValuesPhase.execute(ApplyRequestValuesPhase.java:78)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:312)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
at java.lang.Thread.run(Thread.java:619)
SEVERE: JSF1073: javax.faces.event.AbortProcessingException caught during processing of APPLY_REQUEST_VALUES 2 : UIComponent-ClientId=formaKreiranjeUsluge:tabelaKriterijuma, Message=java.lang.NullPointerException
SEVERE: java.lang.NullPointerException
javax.faces.event.AbortProcessingException: java.lang.NullPointerException
at javax.faces.event.MethodExpressionActionListener.processAction(MethodExpressionActionListener.java:182)
at javax.faces.event.ActionEvent.processListener(ActionEvent.java:88)
at javax.faces.component.UIComponentBase.broadcast(UIComponentBase.java:772)
at javax.faces.component.UICommand.broadcast(UICommand.java:300)
at javax.faces.component.UIData.broadcast(UIData.java:912)
at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:775)
at javax.faces.component.UIViewRoot.processDecodes(UIViewRoot.java:943)
at com.sun.faces.lifecycle.ApplyRequestValuesPhase.execute(ApplyRequestValuesPhase.java:78)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:312)
at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1523)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:279)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:188)
at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:641)
at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:97)
at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:85)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:185)
at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:325)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:226)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:165)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:791)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:693)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:954)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:170)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:135)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:102)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:88)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:76)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:53)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:57)
at com.sun.grizzly.ContextTask.run(ContextTask.java:69)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:330)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:309)
at java.lang.Thread.run(Thread.java:619)
Caused by: java.lang.NullPointerException
at util.ServiceCreatingManager.addPricesToService(ServiceCreatingManager.java:166)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.el.parser.AstValue.invoke(AstValue.java:234)
at com.sun.el.MethodExpressionImpl.invoke(MethodExpressionImpl.java:297)
at javax.faces.event.MethodExpressionActionListener.processAction(MethodExpressionActionListener.java:153)
... 34 more
這顯然沒有什麼選擇，這就是爲什麼拋出NullPointerException。任何幫助？ p.s.如果有些事情難以理解，我會更多解釋。
令人驚訝的是，我發現動作偵聽器在應用請求值階段執行而不是調用動作階段。你不*實際上*有一個'immediate =「true」'放在按鈕上？我無法在您的視圖示例中找到它。但是在按鈕上有一個'immediate =「true」'至少可以解釋爲什麼在調用動作的時候模型沒有被選定的值更新。 – BalusC
是的，我在按鈕上有'immediate =「true」'，但有或沒有異常。 – BojanSM
@BalusC 一切其實都很簡單。我想要checkBox列和按鈕的dataTable，當我按下並調用某些方法時，可以訪問選定的（選中）項目。 – BojanSM