File FTP in Java.doc

FTP file upload code with Java open source FTP API documentation

import java.io.IOException;
import java.io.PrintWriter;
import java.net.InetAddress;
import org.apache.commons.net.ProtocolCommandListener;
import org.apache.commons.net.ftp.FTPClient;
import org.apache.commons.net.ftp.FTPReply;

/***
 * This is an example program demonstrating how to use the FTPUtil class.
 * This program arranges a server to server file transfer that transfers
 * a file from host1 to host2.  
  <p>
 * Usage: ftp <host1> <user1> <pass1> <file1> <host2> <user2> <pass2> <file2>
 * <p>
 ***/
public class FTPUtil
{

    public static final void main(String[] args)
    {
        String server1, username1, password1, file1;
        String server2, username2, password2, file2;
        FTPClient ftp1, ftp2;
        ProtocolCommandListener listener;

        if (args.length < 8)
        {
            System.err.println(
                "Usage: ftp <host1> <user1> <pass1> <file1> <host2> <user2> <pass2> <file2>"
            );
            System.exit(1);
        }
        // these details will be taken from Application Config File
        //////
        server1 = args[0];  
        username1 = args[1];
        password1 = args[2];
        file1 = args[3];
        server2 = args[4];
        username2 = args[5];
        password2 = args[6];
        file2 = args[7];

        listener = new PrintCommandListener(new PrintWriter(System.out));
        ftp1 = new FTPClient();
        ftp1.addProtocolCommandListener(listener);
        ftp2 = new FTPClient();
        ftp2.addProtocolCommandListener(listener);

        try
        {
            int reply;
            ftp1.connect(server1);
            System.out.println("Connected to " + server1 + ".");

            reply = ftp1.getReplyCode();

            if (!FTPReply.isPositiveCompletion(reply))
            {
                ftp1.disconnect();
                System.err.println("FTP server1 refused connection.");
                System.exit(1);
            }
        }
        catch (IOException e)
        {
            if (ftp1.isConnected())
            {
                try
                {
                    ftp1.disconnect();
                }
                catch (IOException f)
                {
                    // do nothing
                }
            }
            System.err.println("Could not connect to server1.");
            e.printStackTrace();
            System.exit(1);
        }

        try
        {
            int reply;
            ftp2.connect(server2);
            System.out.println("Connected to " + server2 + ".");

            reply = ftp2.getReplyCode();

            if (!FTPReply.isPositiveCompletion(reply))
            {
                ftp2.disconnect();
                System.err.println("FTP server2 refused connection.");
                System.exit(1);
            }
        }
        catch (IOException e)
        {
            if (ftp2.isConnected())
            {
                try
                {
                    ftp2.disconnect();
                }
                catch (IOException f)
                {
                    // do nothing
                }
            }
            System.err.println("Could not connect to server2.");
            e.printStackTrace();
            System.exit(1);
        }

__main:
        try
        {
            if (!ftp1.login(username1, password1))
            {
                System.err.println("Could not login to " + server1);
                break __main;
            }

            if (!ftp2.login(username2, password2))
            {
                System.err.println("Could not login to " + server2);
                break __main;
            }

            // Let's just assume success for now.
            ftp2.enterRemotePassiveMode();

            ftp1.enterRemoteActiveMode(InetAddress.getByName(ftp2.getPassiveHost()),
                                       ftp2.getPassivePort());

            
            if (ftp1.remoteRetrieve(file1) && ftp2.remoteStoreUnique(file2))
            {.
                ftp1.completePendingCommand();
                ftp2.completePendingCommand();
            }
            else
            {
                System.err.println(
                    "Couldn't initiate transfer.  Check that filenames are valid.");
                break __main;
            }

        }
        catch (IOException e)
        {
            e.printStackTrace();
            System.exit(1);
        }
        finally
        {
            try
            {
                if (ftp1.isConnected())
                {
                    ftp1.logout();
                    ftp1.disconnect();
                }
            }
            catch (IOException e)
            {
                // do nothing
            }

            try
            {
                if (ftp2.isConnected())
                {
                    ftp2.logout();
                    ftp2.disconnect();
                }
            }
            catch (IOException e)
            {
                // do nothing
            }
        }
    }
}