In a JSP, how can I dynamically set the contentType?

Question

I have a very simple JSP that looks like this:

<%@ page contentType="application/json" %>${actionBean.response}

actionBean.response returns a String. Sometimes that string is json which has a contentType of "application/json" but sometimes that string is jsonp which has a contentType of "application/javascript". But I can't figure out how to dynamically set the value of the contentType.

1. I've tried using <c:choose> around the contentType but it gives me an error saying that I can't set the contentType twice.
2. I've tried using EL for the value of attribute, but it doesn't get expanded.

Is there a way to dynamically set this value?

Answer 1

You could try using scriptlets (not ideal, but I'm not sure there's another way), like this:

<%
    if (actionBean.isJson()) {
        response.setContentType("application/json");
    } else if (actionBean.isJsonp()) {
        response.setContentType("application/javascript");
    }
%>

Edit: And as Joop mentions in the comments, make sure you aren't setting a contentType using a @page directive.