例子:
<s:textfield id="smsInterface.schedule_time" name="smsInterface.schedule_time">
<s:param name="value">
<s:date name="smsInterface.schedule_time" format="yyyy-MM-dd HH:mm" />
</s:param>
</s:textfield>
意指:给s:textfield的value属性赋值为<s:date name="smsInterface.schedule_time" format="yyyy-MM-dd HH:mm" />所代表的字符串的值