Run a JSP file from within a servlet, then get the result into a string?
I'm trying to create a very simple MVC structure with a composite view. Right now it's just has to be a simple:
--
HEADER (common on all pages)
CONTENT (dynamic)
FOOTER (common)
-
I've got a FrontController class which currently loads the layout with a header and footer, but I'm struggling to see a way to include a dynamic body in the JSP file it dispatches the request to:
The layout.jsp file:
<!DOCTYPE html PUBLIC"-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>Personal Website</title>
<link rel="stylesheet" type="text/css" href="/css/main.css" />
</head>
<body>
Header here
<div>
<h1><%= request.getAttribute("contentFile") %></h1>
<jsp:include page="<%= (String)request.getAttribute("contentFile") %>" flush="true" />
</div>
Footer here
</body>
</html>
The FrontController servlet:
/**
* The FrontController which all web requests communicate to.
* The front controller delegates requests to individual action controllers.
* @author Chris Corbyn <chris@w3style.co.uk>
*/
package org.w3style.controllers;
import java.io.*;
import java.util.*;
import javax.servlet.*;
import javax.servlet.http.*;
/**
* FrontController class.
*/
publicclass FrontControllerextends HttpServlet{
/**
* Handle GET requests over HTTP.
* @param HttpServletRequest The request
* @param HttpServletResponse The response
* @throws ServletException
* @throws IOException
*/
publicvoid doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException{
req.setAttribute("contentFile","/view/home.jsp");//This will actually be dynamic
ServletContext app = getServletContext();
RequestDispatcher disp;
disp = app.getRequestDispatcher("/view/_layout/layout.jsp");
disp.forward(req, resp);
}
}
This works, but it goes against my desired logic. Right now this happens:
Front controller dispatches (currently just GET)
Front Controller sets the content-body path
Front Controller dispatches to layout.jsp
layout.jsp includes the dynamic part at runtime.
What I want to happen:
Front Controller dispatches
Front controller executes another servlet (an action controller) for the requested page
Result of that execution stored in a string (the markup basically)
Front Controller dispatches to layout.jsp which includes the dynamic content
The problem with blindly including a JSP file with no action controller being run first is that each page has no control over things like headers. I also like to add functionality for disabling the layout.jsp too (for AJAX requests etc).
I know it's a lot to ask, but can anyone post a basic example of how they include a dynamic body into a common template. The MVC stuff is not so important... I can fathom that out myself :)
I'm coming from a PHP5 background to JSP so I need to rewire my brain a bit :P
