Dynamically include JSP file?

[Joona I Palaste]

Can I somehow dynamically decide which JSP file to include in another
JSP file, using the <%@include%> tag? Specifically, what I want to do is
something like this:

In the main JSP file:
String jspFile = getJSPFileName();
<%@include file= jspFile %>

So that the value of the variable jspFile is the name of the JSP file
being included in the main JSP file. I don't want to use a chain of
if (jspFile.equals("...")) statements, as that would defeat my whole
purpose.
Thanks for your help!

 

[Michael Borgwardt]

Can I somehow dynamically decide which JSP file to include in another
JSP file, using the <%@include%> tag?

No, because the include directive effectively copies the included
page's text into your JSP before it's even compiled!

Instead, you have to use an include action:

<jsp:include page='<%= jspFile %>' />

 

[Tor Iver Wilhelmsen]

No, because the include directive effectively copies the included
page's text into your JSP before it's even compiled!

Yes, but you can surround <%@include %> directives with if/else; but
the result would be one huge servlet, because of the inlining ou
mention. Dynamic includes as you mentioned are better.

 

[Joona I Palaste]

No, because the include directive effectively copies the included
page's text into your JSP before it's even compiled!

Instead, you have to use an include action:

<jsp:include page='<%= jspFile %>' />

This doesn't work at all. I tried the following JSP code:

// Decide which kind of document to render (html/printable/pdf)
String jspFile = Web.getInstance().getJSP(request);
<jsp:include page='<%= jspFile %>' flush="true"/>

and got this Apache Tomcat error:

An error occurred between lines: 1 and 4 in the jsp file: /ok.jsp

Generated servlet error:
/tmp/ok$jsp.java:63: Missing term.
String jspFile =
Web.getInstance().getJSP(request);
^


An error occurred between lines: 1 and 4 in the jsp file: /ok.jsp

Generated servlet error:
/tmp/ok$jsp.java:64: Invalid character constant.
<jsp:include page='<%= jspFile
^


An error occurred between lines: 1 and 4 in the jsp file: /ok.jsp

Generated servlet error:
/tmp/ok$jsp.java:64: ';' expected.
<jsp:include page='<%= jspFile
^

The relevant part of the ok$jsp.java source code is as follows:

// Decide which kind of document to render
(html/printable/pdf)
String jspFile = Web.getInstance().getJSP(request);
<jsp:include page='<%= jspFile
// end
// HTML // begin [file="/ok.jsp";from=(3,35);to=(5,0)]
out.write("' flush=\"true\"/>\n%>\n");

// end

It appears that the JSP compiler does not understand the <jsp:include>
tag at all. Is it possible that it is not supported in Apache Tomcat
4.0.6? Do I have to use a big chain of if/else statements now?

 

[Ryan Stewart]

This doesn't work at all.

Have a look at
http://java.sun.com/j2ee/1.4/docs/api/javax/servlet/RequestDispatcher.html

 

[Joona I Palaste]

This doesn't work at all. I tried the following JSP code:

// Decide which kind of document to render (html/printable/pdf)
String jspFile = Web.getInstance().getJSP(request);
<jsp:include page='<%= jspFile %>' flush="true"/>

and got this Apache Tomcat error:

Dang, now I realise my mistake. I've been trying to use the
<jsp:include> action as part of embedded Java code, not as JSP code.
D'oh!