Byte-Range Serving - PLEASE HELP

Question

Hey Everyone,
I am trying to display very large documents from a servlet and need to stream only the requested bytes to the end-user so they don't have to wait for the entire file to download. I have found an example in perl, but I really want a Java version. Currently my code is set to accept byte ranges and will print out the first range of bytes. The problem is on the second request, when I look for Range in the request header, it is null. I have tried this with both PDF and Word documents and I get the same results for both. Any help anyone could give me would be greatly appreciated. I am under a huge deadline and really need the help.
Thanks

Answer 1

Sean,
Here is the method I am calling within my Servlet...Thanks again for your help.
private void sendPDF(HttpServletRequest req, HttpServletResponse resp, String fullDoc) throws IOException
          long fByte;
          long lByte;
          StringTokenizer stok;
          String tok;
          String curRange;
          File ckFile = new File(fullDoc);
          String shortFile = fullDoc.substring(fullDoc.lastIndexOf(File.separator) + 1);
          resp.setHeader("Content-Disposition", "inline;filename=\"" + shortFile + "\"");
          String rangeStr = req.getHeader("Range");
          long contentLength = 0;
          // check to see if there was a range specified, First time in from the request.
          if (rangeStr == null)
               resp.setContentLength((int) (new File(fullDoc)).length());
               resp.setHeader("Accept-ranges", "bytes");
               FileInputStream fis = new FileInputStream(fullDoc);
               BufferedOutputStream out = new BufferedOutputStream(resp.getOutputStream());
               byte[] inputLine = new byte[1024];
               int numRead = 0;
               int byteCounter = 0;
               resp.setContentType("application/pdf");
               shortFile = fullDoc.substring(fullDoc.lastIndexOf(File.separator) + 1);
               try
                    while ((numRead = fis.read(inputLine)) != -1)
                         byteCounter += numRead;
                         out.write(inputLine, 0, numRead);
                         for (int y = 0; y < 10000; y++);
                    fis.close();
                    out.close();
               catch (SocketException se)
                    fis.close();
          else
               // remove the "bytes=" off the front of the range string
               rangeStr = rangeStr.substring(rangeStr.indexOf("=") + 1);
               // now divide up the ranges into their groups
               StringTokenizer ranges = new StringTokenizer(rangeStr, ",");
               long fileSize = (new File(fullDoc)).length();
               // go through and verify the ranges are valid
               while (ranges.hasMoreTokens())
                    // get the next range set
                    curRange = ranges.nextToken();
                    // breakup the range set
                    stok = new StringTokenizer(curRange, " ,-");
                    tok = stok.nextToken();
                    // convert the first range to a long value
                    fByte = (new Integer(tok)).longValue();
                    lByte = fileSize;
                    // if there is a second value, convert it too
                    if (stok.hasMoreTokens())
                         lByte = (new Integer(stok.nextToken())).longValue();
                    // test to make sure the ranges are valid
                    if (fByte < 0 || fByte > lByte || lByte > fileSize)
                         // error in range
                         return;
                    contentLength += lByte - fByte + 1;
               // the ranges are valid, since we pulled out all of the tokens
               // to check the ranges we need to tokenize again
               // now divide up the ranges into their groups
               ranges = new StringTokenizer(rangeStr, ",");
               // set some header stuff
               String boundary = "multipart";
               resp.setStatus(HttpServletResponse.SC_PARTIAL_CONTENT);
               resp.setHeader("Accept-ranges", "bytes");
               resp.setHeader("Content-Length", String.valueOf(contentLength));
               resp.setHeader("Content-Range", rangeStr);
               resp.setContentType("multipart/x-byteranges; boundary=" + boundary);
               // open the output stream
               ServletOutputStream out = resp.getOutputStream();
               out.flush();
               while (ranges.hasMoreTokens())
                    curRange = (String) ranges.nextElement();
                    stok = new StringTokenizer(curRange, " ,-");
                    long fTok = (new Integer(stok.nextToken())).longValue();
                    if (stok.hasMoreTokens())
                         fByte = fTok;
                         lByte = (new Integer(stok.nextToken())).longValue();
                    else
                         if (curRange.startsWith("-"))
                              fByte = fileSize - fTok;
                              lByte = fileSize;
                         else
                              fByte = 0;
                              lByte = fTok;
                    long bytesToRead = lByte - fByte + 1;
                    out.println();
                    out.println("--" + boundary);
                    out.println("Content-type: application/pdf");
                    out.println("Content-Range: bytes " + fByte + "-" + lByte + "/" + fileSize);
                    out.println();
                    // open the file and send it!
                    FileInputStream fis = new FileInputStream(fullDoc);
                    fis.skip(fByte);
                    byte[] inputLine = new byte[1024];
                    int bytesRead = 0;
                    try
                         while (bytesToRead > 0)
                              if (bytesToRead < inputLine.length)
                                   bytesRead = fis.read(inputLine, 0, (int) bytesToRead);
                              else
                                   bytesRead = fis.read(inputLine);
                              if (bytesRead < 0)
                                   break;
                              bytesToRead -= bytesRead;
                              // write the bytes out to the browser
                              out.write(inputLine, 0, bytesRead);
                              out.flush();
                         if (bytesToRead != 0) System.out.println("bytesToRead is not zero: " + bytesToRead);
                         fis.close();
                         out.flush();
                    catch (SocketException se)
                         fis.close();
               // close the current boundary
               out.println();
               out.println("--" + boundary + "--");
               // close the output stream
               out.close();