url = "\\serveur\repertoire1\repertoire2\;
File newFichierServer = new File(url);
..
 public static void copyFile(InputStream uploadInStream, File newFichierServer) throws IOException {
        byte[] buffer = new byte[8192];
        FileOutputStream fOut = new FileOutputStream(newFichierServer);
        int c = 0;
        while ((c = uploadInStream.read(buffer)) != -1) {
            fOut.write(buffer, 0, c);
        }
        fOut.flush();
        fOut.close();
    }
...
newFichierServer.setReadOnly();