Jsp If条件判断问题.

Question

新手:
tomcat+struts 2.0
jsp 页面直接关联model
现在需要根据model(admin)里面的一个item(id),判断jsp页面出现的内容.
大概流程:
...
<table>
<tr>
<td><s:if admin.id is null>   ---这个地方不知道怎么写  , admin.id是String类型
<s:text name="admin.name"></s:text>
</s:if>
<s:else>
<s:text name="admin.title"></s:text>
</s:else></td>
</tr>
</table>
...

Answer 1

<s:if test="#admin.name == null">

Answer 2

1.<s:if test="admin.id == null">2.<s:if test="%{admin.id == null}">3.<s:if test="%{#request.admin.id == null}">

Answer 3

4. <s:if test="#request.admin.id == null"> 

Answer 4

谢谢ls两位的回复.经过测试.
1. <s:if test="admin.id == null"> 2. <s:if test="%{admin.id == null}"> 3. <s:if test="%{#request.admin.id == null}"> 4. <s:if test="#request.admin.id == null"> 
都能达到我的要求.

Answer 5

1. <s:if test="admin.id == null">2. <s:if test="%{admin.id == null}">3. <s:if test="%{#request.admin.id == null}">4. <s:if test="#request.admin.id == null">