JSF 中 分页的问题

如题， 在JSF中实现分页， 我写的代码如下 但是第二页没有数据    各位大侠帮下忙<rich:datascroller id="chartList1" for="snapshot_list" maxPages="6" reRender="chartList2" fastStep="7"/>
<rich:dataTable
value="#{chartMgmtControllerBean.charts}" var="chart"
id="snapshot_list" cellpadding="0" cellspacing="0"
styleClass="group_item_list_table" rows="7">
<rich:column styleclass="group_item_row">
<f:facet name="header">Name</f:facet>
<h:outputText value="#{chart.name}" />
</rich:column>
<rich:column styleclass="group_item_row">
<f:facet name="header">Action</f:facet>
<h:commandLink action="#{snapshotSearchController.viewSnapshot}">
<h:graphicImage value="/images/view_details.gif"
style='border-width: 0px;' title="View Detail"/>
<f:param name="snapshotId" value="#{chart.id}" />
</h:commandLink>
<rich:spacer width="5" />
<h:commandLink action="#{snapshotDeleteController.deleteSnapshot}">
<h:graphicImage value="/images/delete.gif"
style='border-width: 0px;' title="Delete"/>
</h:commandLink>
<rich:spacer width="5" />
<h:commandLink action="#{snapshotEditController.editSnapshot}">
<h:graphicImage value="/images/edit_properties.gif"
style='border-width: 0px;' title="Edit"/>
</h:commandLink>
</rich:column>
</rich:dataTable>
<rich:datascroller id="chartList2" for="snapshot_list" maxPages="10" reRender="chartList1"/>