How to resume download with HTTP

Question

I am trying to make it so that I can resume downloading through an HTTP connection. I currently create the connection and get the InputStream and then call skip(long n). This doesn't work because it redownloads all of the information and then just ignores them. I was wondering if anyone knows of a way that I can accomplish this? Thanks,
Dave

Answer 1

I actually figured this out while reading the HTTP specs and I need to do exactly what you said. Here's the code that I used to do it:
private InputStream getInputStream(String strURL, long offset)
     try
          URL url = new URL(strURL);
          URLConnection uc = url.openConnection();
          uc.setRequestProperty("Authorization", "Basic " + (new BASE64Encoder()).encode("username:password".getBytes()));
          if ((offset != 0) && uc.getHeaderField(0).toUpperCase().startsWith("HTTP/1.1"))
               uc.setRequestProperty("Range", "bytes=" + offset + "-");
          return uc.getInputStream();
     catch (MalformedURLException mfURLe)
          System.err.println("Malformed URL in Client Updater. Unable to receive update list: " + mfURLe.getMessage());
     catch (IOException ioe)
          System.err.println("Unable to open input stream: " + ioe.getMessage());
     return null;
}