URLConnection cannot flush

Hi
   I am using the following function to post a file to the web server.
But i found out the DataOutputStream::flush() cannot flush the data,
it seem to cache the whole query before send it out. Some people have
discovered this problem before : http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5026745
But how to fix it? I need to add a progress bar to my app, so i need
to know how many byte have been send out.

thanks
from Peter (cmk128@hotmail.com)

private boolean uploadFile(File file, String relativePath, int
rowNumber) {
        try {
            URL u = new URL("http://microsoft.com/test.php");
            URLConnection c = u.openConnection();
            // post multipart data
            c.setDoOutput(true);
            c.setDoInput(true);
            c.setUseCaches(false);
            // set some request headers
            c.setRequestProperty("Connection", "Keep-Alive");
            c.setRequestProperty("Cache-Control", "no-cache");
            c.setRequestProperty("HTTP_REFERER",
                                 "http://pvs.kingofcoder.com/
test.php");
            c.setRequestProperty("Content-Type",
                                 "multipart/form-data; charset=utf-8;
boundary=****4353");
            DataOutputStream dstream = new
DataOutputStream(c.getOutputStream());

            // write currentpath
            dstream.writeBytes("--****4353\r\n");
            dstream.writeBytes(
                    "Content-Disposition: form-data; name=\"currentPath
\"\r\n\r\n");
//
dstream.writeBytes(URLEncoder.encode(this.getParameter("currentpath"),
"UTF-8"));
            String currentPath = (getParameter("currentPath") ==
null) ? "" :
                                 getParameter("currentPath");
            dstream.writeBytes(currentPath);
            dstream.writeBytes("\r\n");

            // write relativePath
            dstream.writeBytes("--****4353\r\n");
            dstream.writeBytes(
                    "Content-Disposition: form-data; name=
\"relativePath\"\r\n\r\n");
            dstream.writeBytes(relativePath);
            dstream.writeBytes("\r\n");

            // write filename
            dstream.writeBytes("--****4353\r\n");
            dstream.writeBytes(
                    "Content-Disposition: form-data; name=
\"uploadedFile\"; filename=\"" +
                    file.getName() +
                    "\"\r\nContent-Type: application/octet-stream\r\n\r
\n");

            //write file content
            FileInputStream fi = new FileInputStream(file);
            byte[] bt = new byte[102400];
            int cnt = fi.read(bt);
            int numOfByteSent = cnt;
            while (cnt == bt.length) {
                dstream.write(bt, 0, cnt);
                dstream.flush();
                cnt = fi.read(bt);
                numOfByteSent += cnt;
                pMainTableModel.getStatus().set(rowNumber,
 
String.valueOf(numOfByteSent /
                        file.length()));
                System.out.println(">" + numOfByteSent);
                pMainTableModel.fireTableDataChanged();
            }
            dstream.write(bt, 0, cnt);
            dstream.flush();
            pMainTableModel.getStatus().set(rowNumber, "100");

            dstream.writeBytes("\r\n--****4353--\r\n\r\n");
            dstream.flush();
            dstream.close();
            fi.close();
            // end write file content

            try {
                DataInputStream in =
                        new DataInputStream(c.getInputStream());
                String sIn;
                while ((sIn = in.readLine()) != null) {
                    if (sIn != null) {
                        System.out.println(sIn);
                    }
                    if (sIn.equals("upload success")) {
                        return true;
                    }
                }
                return false;
            } catch (Exception ex) {
                ex.printStackTrace();
                return false;
            }
        } catch (Exception ex2) {
            ex2.printStackTrace();
            return false;
        }
    }