JSP include directive, jsp:include action, relative vs. absolute paths

Question

I am doing some basic templating in my JSP-based webapp. For example, I want to have a standard header and footer (basic HTML) that I pull into each of my JSPs.

My content JSP is at /WEB-INF/jsp/home.jsp, and I have template JSPs at /WEB-INF/jsp/template/, such as /WEB-INF/jsp/template/Body-Footer.jsp.

So now, within home.jsp, I want to pull in my template files. First, I try the jsp:include action:

<jsp:include page="template/Body-Footer.jsp"></jsp:include>

It generates the error javax.servlet.ServletException: File "/template/Body-Footer.jsp" not found

Strange to me, considering that Eclipse says that the path is valid.

Okay, so then I switch to the include directive:

<%@ include file="template/Body-Footer.jsp" %>

This works just fine, pulls in my footer HTML.

But why does the jsp:include not work? After some experimentation, I find that putting in the absolute path does get it to work:

<jsp:include page="/WEB-INF/jsp/template/Body-Footer.jsp"></jsp:include>

Now it works fine, no errors.

So here's my question: why? Why do I (apparently) need to use an absolute path with the jsp:include action, but not with the include directive?

Answer 1

/WEB-INF/jsp/template/Body-Footer.jsp is not an absolute path. Its also a relative path. The problem is that template/Body-Footer.jsp is an incomplete relative path, whereas the other is complete. That is, the paths are relative to your app path. Since /WEB-INF/ is under your app path, you have to include it. Absolute path means like C:/program files/tomcat/webapps/yourapp/WEB-INF/jsp/template/Body-Footer.jsp

Answer 2

Answer to WHY - The jsp:include is a runtime directive unlike the <%@ include ... %> directive which happens to be a compile time directive (translation time, actually).

See more on: JSP Performance using jsp:include

Bottom line - directives are run against different folders as a base.

Btw. JSP pages should be outside of WEB-INF folder, if you want to follow official recommendation:

The Java EE 6 Tutorial - Web Module Structure

Answer 3

I read JSP 2.0 spec and here:

 Relative URL Specifications

 * A context-relative path is a path that starts with a slash (/).
 It is to be interpreted as relative to the application to which
 the JSP page or tag file belongs. That is, its ServletContext
 object provides the base context URL.

 * A page relative path is a path that does not start with a
 slash (/). It is to be in- terpreted as relative to the current
 JSP page, or the current JSP file or tag file, depending on where
 the path is being used.

For now javax.servlet.ServletContext.getRealPath("/WEB-INF/test/test.jsp") is null for security reason.

Assume that context-relative path is path from your WAR root.