声明URL
<s:url action="downloadDocumentItem" id="downloadDocumentItem">
<s:param name="id" value="id"></s:param>
</s:url>
<s:url action="updatePDocumentItem" id="updatePDocumentItem">
<s:param name="id" value="id"></s:param>
</s:url>
引用URL
<a href='<s:property value="#downloadDocumentItem"/>'>下载</a>