How do I include JSTL variables from another file? - jstl

Question

I would like to have a JSTL file of "constants" and reference them in other files.
e.g.
constants.jsp:
<%# taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<c:set var="colour" value="blue"/>
<c:set var="car">Audi</c:set>
Other file:
<%# taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<c:import url="constants.jsp"/>
<p>I drive an ${car} which is ${colour}</p>
The code above (obviously) does not work. How can I get something similar to work?
Bonus points if I can use namespaces as well.

Answer 1

You could use an include directive:
<%#include file="/constants.jsp" %>
Or you could use a dynamic include, but then the variables would have to be stored in the request, rather than the page scope:
<jsp:include page="/constants.jsp" />
<c:set var="colour" value="blue" scope="request"/>
<c:set var="car" scope="request">Audi</c:set>
But the best way would probably be to put all these constants in an object, and store this object in the request (or session, or application) from a servlet or filter:
private class Constants {
private String color = "blue";
private String car = "Audi";
public String getColor() {
return color;
}
public String getCar() {
return car;
}
}
...
request.setAttribute("constants", new Constants());
...
<p>I drive an ${constants.car} which is ${constants.color}</p>