Question

Assuming that requestScope.importMe is expecting a path to a JSP file

<c:choose>
    <c:when test="${!empty requestScope.importMe && fileExists(requestScope.importMe) }">
    <c:import url="${requestScope.importMe}" />   
    ...
</c:choose>

How can I check if the file exists before trying to include it so that an error is not thrown?

I’d prefer a solution using JSTL tags.

Answer 1

Put it in a c:catch tag. It will catch any thrown Exception for you.

<c:catch var="e">
    <c:import url="${url}" />
</c:catch>
<c:if test="${!empty e}">
    Error: ${e.message}
</c:if>

I must however admit that I don’t like the c:catch approach. It’s abusing exceptions to control the flow. If you can, rather do this job in a servlet or JavaBean instead with help of File#exists() (and ServletContext#getRealPath()).