Escape JSP EL using JSTL tags (dot character)

Question

Some frameworks (Spring, Tomcat itself) add servlet request attributes that cannot be used within an EL expression by default. An example would be

javax.servlet.forward.context_path = /myWebapp

So, to get the value using JSTL I'd normally use

<c:out value="${javax.servlet.forward.context_path}" />

However that's not working because the EL parser expects javaxto be the key of object A and servlet to be a property of that object (and so on).

So my question is: How do I escape the dot character?

I've tried using

<c:out value="${javax\.servlet\.forward\.context_path}" />

but that's not working either and raises an error from the EL parser.

I know that when dealing with maps I can use something like

<c:out value="${aMap['key.from.map.with.dots']}" />

but thats not working with a first level object from the request, since I've also tried using

<c:out value="${['javax.servlet.forward.context_path']}" />

which is not working either.

Any ideas?

Luanaluanda

Answer 1

if you know the scope of the attribute, then you can fetch it from the appropriate implicit object, e.g.

${requestScope['javax.servlet.forward.context_path']}

I'm not sure if there's an implicit object that checks all scopes in the way that {xxx} does, though.

Taam