如何使用if，else条件在jsf中显示图像 [英] How to use if, else condition in jsf to display image
问题描述
我有一个条件，即我有一个登记表，其中如果userid为0，则应显示虚拟图像；当我从任何更新中编辑用户时，我检查userid是否等于0，然后显示对应的图像到用户ID.
I have a condition where I have an enrollment form in which if userid is 0 it should show the dummy image and when I edit user from any update, I check for if userid which is not equal to 0 then display the image corresponding to userid.
我在jsf页面中使用了JSTL.但始终会尝试转到else循环以显示图像.该功能运行正常.唯一的问题是，当我第一次访问该页面时，我无法显示虚拟图像.这是我的代码.
I used JSTL inside jsf page. But always it tries to go to else loop for showing image. The functionality is working fine. The only thing is I can't display the dummy image when I visit the page first. Here s my code.:
<c:if test="${'#{user.userId}' == '0'}">
<a href="Images/thumb_02.jpg" target="_blank" ></a>
<img src="Images/thumb_02.jpg" />
</c:if>
<c:otherwise>
<a href="/DisplayBlobExample?userId=#{user.userId}" target="_blank"</a>
<img src="/DisplayBlobExample?userId=#{user.userId}" />
</c:otherwise>
我可以使用此JSTL标记还是可以使用jsf进行标记?
Can I use this JSTL tag or can I do it using jsf?
推荐答案
嵌套EL表达式是非法的:您应该内联它们.在您的情况下，使用JSTL是完全有效的.更正错误后，您将使代码正常工作:
It is illegal to nest EL expressions: you should inline them. Using JSTL is perfectly valid in your situation. Correcting the mistake, you'll make the code working:
<html xmlns="http://www.w3.org/1999/xhtml" xmlns:c="http://java.sun.com/jstl/core">
<c:if test="#{not empty user or user.userId eq 0}">
<a href="Images/thumb_02.jpg" target="_blank" ></a>
<img src="Images/thumb_02.jpg" />
</c:if>
<c:if test="#{empty user or user.userId eq 0}">
<a href="/DisplayBlobExample?userId=#{user.userId}" target="_blank"></a>
<img src="/DisplayBlobExample?userId=#{user.userId}" />
</c:if>
</html>
另一种解决方案是在一个元素的EL内指定所需的所有条件.尽管它可能较重且可读性较差，但它是:
Another solution is to specify all the conditions you want inside an EL of one element. Though it could be heavier and less readable, here it is:
<a href="#{not empty user or user.userId eq 0 ? '/Images/thumb_02.jpg' : '/DisplayBlobExample?userId='}#{not empty user or user.userId eq 0 ? '' : user.userId}" target="_blank"></a>
<img src="#{not empty user or user.userId eq 0 ? '/Images/thumb_02.jpg' : '/DisplayBlobExample?userId='}#{not empty user or user.userId eq 0 ? '' : user.userId}" target="_blank"></img>
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