struts2标签之列求和

struts2标签之列求和<table width="100%" border="0" cellpadding="0" cellspacing="0" class="table_cont">
    <tr class="tr_bg">
      <th>区县</th>
      <th>预售楼数</th>
      <th>可售套数</th>
      <th>签约套数</th>
      <th>签约面积</th>
      <th>房屋均价</th>
     </tr>
    <s:set name="ysBldCount" value="0"></s:set>
     <s:set name="ysHouseCount" value="0"></s:set>
     <s:set name="ysHouseQyCount" value="0"></s:set>
     <s:set name="ysHouseQyArea" value="0"></s:set>
     <s:set name="ysHouseQyMoney" value="0"></s:set>
     <s:iterator id="distbld" value="distBldList" status="info">
           <s:if test="#index.odd==false">
    <tr class="tr_bg">
   </s:if>
   <s:else>
    <tr>
   </s:else>
  <td>${distbld.distname}</td>
  <td>${distbld.bld_num}
      <s:set name="ysBldCount" value="#ysBldCount+#distbld.bld_num"></s:set>
  </td>
  <td>${distbld.house_num}
      <s:set name="ysHouseCount" value="#ysHouseCount+#distbld.house_num"></s:set>
  </td>
  <td>${distbld.house_qy_num}
      <s:set name="ysHouseQyCount" value="#ysHouseQyCount+#distbld.house_qy_num"></s:set>