Saving a file in JSF with a servlet

Question

Okay, here is essentially what I'm doing right now:
1. The user selects some data that they want to export (save) to a file and enters a filename into a text box.
2. The user then clicks an 'Export' button and a controller action is invoked that puts the filename and the data (as a String) into the http session.
3. On success, the controller returns a successForServlet string which a navigation rule defined in faces-config looks at and sends the page to an ExportToFile.jsp page.
4. All this jsp page does is to forward the request to my servlet.
5. The servlet picks up the filename and data from the http session and sets up the appropriate response. This causes a 'Save' dialog to be prompted to the user so that they can choose a location and such.
6. The user clicks save and the file is saved to disk.
This all works wonderfully. BUT, here is the problem...I am now out of JSF's scope since the nav rule sent the request (ultimately) to a servlet. The page that the user was on is now stale and they have to click a menu item or something to get back into JSF scope. So, what now? I've tried a few things that I won't mention here until I see what kind of suggestions I get from you guys. Thanks to anyone that can help me out. Lance.

Answer 1

I may not be understanding you correctly (this is very new to me), but I tried your suggestion to no avail. As I understood it, you were suggesting that I put this into my servlet. I did so in a finally block in my doPost() method. Here's the code:
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String methodName = "doPost";
log_.entry(methodName);
try {
// Get a session-scoped value
HttpSession session = request.getSession();
String exportFileName = (String) session.getAttribute( "ExportEntityFileName" );
String exportString = (String) session.getAttribute( "ExportEntityText" );
response.setHeader("Pragma", "No-cache");
response.setDateHeader("Expires", 0);
response.setHeader("Cache-Control", "no-cache");
response.setHeader("Content-Disposition", "attachment; filename=" + exportFileName + ".txt");
response.setHeader("Context-Type", "text/html");
response.getOutputStream().write(exportString.getBytes());
} catch (Exception e) {
log_.error(e.toString());
} finally {
HttpSession session = request.getSession();
session.setAttribute("ExportEntityFileName", null);
session.setAttribute("ExportEntityText", null);
response.getOutputStream().close();
session.getServletContext().getRequestDispatcher("/appPanels/utilities/BcfExport.jsp");
log_.exit(methodName);
Something about this line:
session.getServletContext().getRequestDispatcher("/appPanels/utilities/BcfExport.jsp");
...didn't look right, so I tried this also:
session.getServletContext().getRequestDispatcher("/appPanels/utilities/BcfExport.jsp").forward(request, response);
...but that was no help either. Any more suggestions out there? I can't believe that this isn't being done by others. I mean, saving a file to disk!?!?!?!? It sounds rather elementary.
Thanks for any suggestions.