displaytag标题栏合并的非典型性实现

<display:table name="requestScope.result" clearStatus="true" keepStatus="true" pagesize="10" requestURI="XXAction.do" uid="table1">
	<display:column title="col1</th><th colSpan='2'>col2_3">
		<bean:write  name="table1" property="col1" />
		</td>

		<td>
		<bean:write  name="table1" property="col2" />
		</td>

		<td>
		<bean:write name="table1" property="col3"/>
	</display:column>
</display:table>