struts中标签的嵌套

Question

 <form action="#" method="post">
    照片名：<input type="text" name="photo.photoName" value="${request.oldPhotoInfo.photoName}"/><br/>
    说　明：<textarea rows="2" cols="18"><s:property value="#request.oldPhotoInfo.photoExplain"/></textarea><br/><s:property value='#request.oldPhotoInfo.folderId'/>
    相　册：<select name="photo.folderId">
      <s:iterator var="folder" value="#request.folderList" status="state">
      <s:if test="#folder.folderId==<s:property value='#request.oldPhotoInfo.folderId'/>">
      <option value="${folder.folderId}">${folder.folderName}</option>
      </s:if>
      
      </s:iterator>
    </select><br/>
    <input type="submit" value="修改"/>
    </form>

 

以上代码s:if中判断是失败的，不知道为什么。求快速正解