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>
  </td>
  <td>${distbld.house_qy_area}
      <s:set name="ysHouseQyArea" value="#ysHouseQyArea+#distbld.house_qy_area"></s:set>
  </td>
  <td>${distbld.house_avg_money}
      <s:set name="ysHouseQyMoney" value="#ysHouseQyMoney+#distbld.house_avg_money"></s:set>
  </td>
</tr>
</s:iterator>
<tr><td>全市</td><td>${ysBldCount} </td><td>${distbld.house_num}</td><td>${distbld.house_qy_num}</td><td>${ysHouseQyArea}</td><td>${ysHouseQyMoney}</td></tr>
</table>

<s:set var="count" value="0" />
<s:iterator value="categories" id='i' >
<s:if test="#i.parentId != #flag">
<s:set var="count" value="#count+1" />
<s:set name="flag" value="#i.parentId" />
<tr>


<td><s:property value="#count"/></td>
<td>