Gerar relatório com JSF 2.0 + primefaces: DataExporter

gistfile1.java

  				<p:dataTable id="questionario" var="perg"
						value="#{perguntas.listarCadastrarPerguntas}"  paginator="true" rows="10" 
						emptyMessage="Nenhuma pergunta cadastrada.">

						<p:column exportable="false">
							<f:facet name="output">
								<h:outputText value="Pergunta" />
							</f:facet>
							<h:outputText value="#{perg.value}" />
						</p:column>

						<p:column style="display: none">
							<f:facet name="output">
								<h:outputText value="Pergunta1" />
							</f:facet>
							<h:outputText value="#{perg.resposta1}" />
							
						</p:column>

						<p:column>
							<f:facet name="output">
								<h:outputText value="Resposta2" />
							</f:facet>
							<h:outputText value="#{perg.resposta2}" />
						</p:column>

						<p:column>
							<f:facet name="output">
								<h:outputText value="Resposta3" />
							</f:facet>
							<h:outputText value="#{perg.resposta3}" />

						</p:column>

						<p:column headerText="4" style="width:auto">

							<f:facet name="output">
								<h:outputText value="Resposta4" />
							</f:facet>
							<h:outputText value="#{perg.resposta4}" />
						</p:column>

						<p:column>
							<f:facet name="output">
								<h:outputText value="Resposta Correta" />
							</f:facet>
							<h:outputText value="#{perg.respostaCorreta}" />
						</p:column>
					</p:dataTable>



					<!-- Button para gerar PDF - XLS - XML - CSV -->

					<br /> <br />
					<h:panelGrid columns="2">
						<p:panel header="Exportar Relatório">
							<h:commandLink >
								<p:graphicImage value="/img/excel.png" />
								<p:dataExporter type="xls" target="questionario" fileName="sipa" />
							</h:commandLink>

							<h:commandLink ajax="false">
								<p:graphicImage value="/img/pdf.png" />
								<p:dataExporter type="pdf" target="questionario	" fileName="sipa" postProcessor="#{perguntas.cadastrarPergunta}"/>
							</h:commandLink>

							<h:commandLink>
								<p:graphicImage value="/img/csv.png" />
								<p:dataExporter type="csv" target="questionario" fileName="sipa" />
							</h:commandLink>

						</p:panel>
					</h:panelGrid>

					<!-- Fim Button para gerar PDF - XLS - XML - CSV -->