Servlet-client file serialization and Internet Explorer

Question

I've written a servlet that serializes a multi-page tiff file to the requesting user-agent. The servlet works fine with Firefox and Netscape Navigator, opening a dialog to launch the default handler applicaton for the "image/tiff" MIME type, but Internet Explorer chokes on the output, popping up an error dialog that states the following:
Internet Explorer cannot download <icn>.tif from <hostname>
Internet Explorer was not able to open this Internet site. The requested site is either unavailable or cannot be found. Please try again later.
This is on top of a File Download dialog that shows the <icn>.tif being downloaded and a status of "Getting file information"
Here's my servlet code:
* Created on Apr 29, 2005
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
package eds.chico.ddm.web;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.rmi.RemoteException;
import javax.ejb.CreateException;
import javax.ejb.RemoveException;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import eds.chico.ddm.interfaces.ClaimFinder;
import eds.chico.ddm.interfaces.ClaimFinderHome;
* Servlet Class
* @web.servlet              name="ImgSerialize"
*                           display-name="ImgSerialize"
*                           description="ImgSerialize Servlet"
* @web.servlet-mapping      url-pattern="/ImgSerialize"
* @web.servlet-init-param  description="Buffer size used for io during image serialization"
*                                    name="buffSize"
*                          value="512"
* @web.ejb-ref
*           name="ejb/ClaimFinderHome"
*           type="Session"
*           home="eds.chico.ddm.interfaces.ClaimFinderHome"
*           remote="eds.chico.ddm.interfaces.ClaimFinder"
*           description="Reference to the ClaimFinder EJB"
* @jboss.ejb-ref-jndi
*           ref-name = "ejb/ClaimFinderHome"
*           jndi-name = "ejb/ClaimFinderHome"
public class ImgSerialize extends HttpServlet {
     private static final long serialVersionUID = 1;
     private ClaimFinderHome cfHome;
     private ServletConfig cfg;
     public ImgSerialize() {
          super();
          // TODO Auto-generated constructor stub
     public void init(ServletConfig config) throws ServletException {
          super.init(config);
          this.cfg = config;
          try {
               Context ctx = new InitialContext();
               cfHome = (ClaimFinderHome)ctx.lookup("java:comp/env/ejb/ClaimFinderHome");
          } catch (NamingException e) {
               throw new ServletException("EJB Lookup failed", e);
     protected void doGet(HttpServletRequest req, HttpServletResponse resp)
          throws ServletException,
          IOException {
          processRequest(req, resp);
     protected void doPost(
          HttpServletRequest request,
          HttpServletResponse response) throws ServletException, IOException {
          processRequest(request, response);
     private void processRequest(HttpServletRequest req, HttpServletResponse resp) throws ServletException {
          String icn = req.getParameter("icn");
          ClaimFinder cf = null;
          String claimPath = null;
          try {
               cf = cfHome.create();
               claimPath = cf.getClaimPath(icn);
               cf.remove();
          } catch (CreateException e) {
               throw new ServletException("Unable to instantiate ClaimFinder EJB", e);
          } catch (RemoteException e) {
               throw new ServletException("ClaimFinder remote exception", e);
          } catch (RemoveException e) {
               // Hmmm... probably okay to do nothing
          if (claimPath == null) {
               throw new ServletException("claimPath is null after lookup");
          File imageFile = new File(claimPath);
          byte[] buff = new byte[new Integer(cfg.getInitParameter("buffSize"))];
          try {
               BufferedInputStream bis = new BufferedInputStream(new FileInputStream(imageFile));
               resp.setContentType("image/tiff");
               BufferedOutputStream bos = new BufferedOutputStream(resp.getOutputStream());
               while (bis.read(buff) != -1) {
                    bos.write(buff);
               bis.close();
               bos.close();
          } catch (IOException e) {
               throw new ServletException("java.io error", e);
}Unfortunately, the target users for this application will be using Internet Explorer, so I must find a way to make this code work with IE6. Anyone have any thoughts?
Greg Adams

Answer 1

// assume you have an object representing a file, mine is not coming from disk, but from a blob in the database.
     response.setContentLength( (int) file.getFileSize());
     response.setHeader("Content-Type", ResponseUtil.getContentType(file.getFileName()));
     // use inline or attachment depending upon whether you want the file to open within the browser,
     // or in a separate window.
     //response.setHeader("Content-Disposition","attachment; filename=\""+file.getFileName()+"\"");
     response.setHeader("Content-Disposition","inline; filename=\""+file.getFileName()+"\"");
        // Cache-control, some comments on different choices       
        //no cache header at all // works ok in IE and FireFox
        //response.setHeader("Cache-control", "no-cache"); // works in FireFox, but not IE       
        response.setHeader("Cache-control", "must-revalidate"); // works in IE and FireFox
        ServletOutputStream out = response.getOutputStream();
        out.write(file.getFileBytes());
   public static final String CONTENT_TYPE_GIF = "image/gif";
   public static final String CONTENT_TYPE_JPG = "image/jpeg";
   public static final String CONTENT_TYPE_TXT = "text/html";
   public static final String CONTENT_TYPE_XML = "text/xml";
   public static final String CONTENT_APPLICATION_OCTET_STREAM = "application/octet-stream";
    * By setting the response content type, we are advising the user's agent (browser)
    * which application to use to open the document, and whether or not the application
    * will run within the browser.
    * e.g., Our handling of xls files launches a dialog to open or save the xls file,
    * and the excel application is run independent of the browser.
   public static String getContentType(String filename)
      String responseContentType = CONTENT_APPLICATION_OCTET_STREAM;
      if (filename.toLowerCase().endsWith("html") || filename.toLowerCase().endsWith("htm"))
         responseContentType = CONTENT_TYPE_TXT;
      else if (filename.toLowerCase().endsWith("jpg") || filename.toLowerCase().endsWith("jpeg"))
         responseContentType = CONTENT_TYPE_JPG;
      else if (filename.toLowerCase().endsWith("gif"))
         responseContentType = CONTENT_TYPE_GIF;
      else if (filename.toLowerCase().endsWith("xml"))
         responseContentType = CONTENT_TYPE_XML;
      //TODO handle other file types
      return responseContentType;
   }