A class to illustrate the use of Apache Commens Net FTP connection. The FTPClient verifies and establishes a connection to an FTP server.

FileTransfer.java

/**
 * A class to illustrate the use of Apache Commens Net FTP connection.
 *
 * @author Kranthi Lakum
 */
public class FileTransfer
{
   private static FTPClient theFtpClient = new FTPClient();
   private static int theCode;
   private static Logger myLogger = LoggerFactory.getLogger(FileTransfer.class);

   public static void connect(String parUserName, String parPassword,
                              String parHostName, int parPort)
   {
     try
     {
       theFtpClient.connect(parHostName, parPort);
       theFtpClient.login(parUserName, parPassword);
       theCode = theFtpClient.getReplyCode();
       if(FTPReply.isPositiveCompletion(theCode))
       {
         System.out.println("Connection Success!");
       }
       else
       {
         System.out.println("Connection Failed.");
         theFtpClient.disconnect();
       }
     }
     catch (SocketException e1)
     {
       myLogger.error("Socket unresponsive on server.");
     }
     catch (IOException e2)
     {
      myLogger.error("An I/O error while talking to server.");
     }
     finally
     {
        if(theFtpClient.isConnected())
        {
          try
          {
            theFtpClient.disconnect();
          }
          catch(IOException ioe)
          {
            // do nothing
          }
      }
   }

   public static void main (String[] args)
   {
     String theUserName = "username"; // username of an FTP account on server
     String thePassword = "password"; // relevant password
     String theRemoteHost = "127.0.0.1"; // host name or IP address of the FTP server
     int thePortNumber = 21; // port number to listen to
     connect(theUserName, thePassword, theRemoteHost, thePortNumber);
   }
}