Dónal Dónal - 5 months ago 97
Java Question

How to check if a variable exists in a FreeMarker template?

I have a Freemarker template which contains a bunch of placeholders for which values are supplied when the template is processed. I want to conditionally include part of the template if the userName variable is supplied, something like:

[#if_exists userName]
Hi ${userName}, How are you?
[/#if_exists]


However, the FreeMarker manual seems to indicate that if_exists is deprecated, but I can't find another way to achieve this. Of course, I could simple providing an additional boolean variable isUserName and use that like this:

[#if isUserName]
Hi ${userName}, How are you?
[/#if]


But if there's a way of checking whether userName exists then I can avoid adding this extra variable.

Answer
[#if userName??]
   Hi ${userName}, How are you?
[/#if]

Or with the standard freemarker syntax:

<#if userName??>
   Hi ${userName}, How are you?
</#if>