FTP behind proxy

[Alex Ku]

Hi,
I am writing a simple ftp client program to download a file from a ftp site. The site requires login and the ftp client is behind a proxy.
I did find some sample show you how to do FTP. Also, some show you how to work with proxy. But not both.
the following is the codes I use. I got IOException "HTTP response code: 401" if the urlString contains userinfo (ftp://user [e-mail]/file)
But "ftp://ftp.site/file" works fine.
I think the problem is the communication between the java program and the proxy server. Could anyone help me?

  
public void someMethod()
{
  setProxy();
  BufferedOutputStream dest = null;
  BufferedInputStream is = null;
  URL url = new URL(urlString);
  URLConnection urlConn = url.openConnection();
  is = new BufferedInputStream(urlConn.getInputStream());
  FileOutputStream fos = new FileOutputStream(localFile);
  dest = new BufferedOutputStream(fos, 100000);
}
public void setProxy()
{
  Properties systemproperties = System.getProperties();
  systemproperties.put("httpproxyHost", proxyAddress);
  systemproperties.put("httpproxyPort", proxyPort);
  systemproperties.put("httpproxySet","true");
  System.setProperties(systemproperties);
}