Commons Net example source code file (ServerToServerFTP.java)

This example Commons Net source code file (ServerToServerFTP.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Commons Net tags/keywords

check, couldn't, ftpclient, ftpclient, io, ioexception, ioexception, net, network, printcommandlistener, protocolcommandlistener, servertoserverftp, string, string, usage, usage

The Commons Net ServerToServerFTP.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package examples.ftp;

import java.io.IOException;
import java.io.PrintWriter;
import java.net.InetAddress;

import org.apache.commons.net.PrintCommandListener;
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 FTPClient class.
 * This program arranges a server to server file transfer that transfers
 * a file from host1 to host2.  Keep in mind, this program might only work
 * if host2 is the same as the host you run it on (for security reasons,
 * some ftp servers only allow PORT commands to be issued with a host
 * argument equal to the client host).
 * <p>
 * Usage: ftp <host1>       
 * <p>
 ***/
public final class ServerToServerFTP
{

    public static final void main(String[] args)
    {
        String server1, username1, password1, file1;
        String server2, username2, password2, file2;
        String [] parts;
        int port1=0, port2=0;
        FTPClient ftp1, ftp2;
        ProtocolCommandListener listener;

        if (args.length < 8)
        {
            System.err.println(
                "Usage: ftp <host1>       "
            );
            System.exit(1);
        }

        server1 = args[0];
        parts = server1.split(":");
        if (parts.length == 2) {
            server1=parts[0];
            port1 = Integer.parseInt(parts[1]);
        }
        username1 = args[1];
        password1 = args[2];
        file1 = args[3];
        server2 = args[4];
        parts = server2.split(":");
        if (parts.length == 2) {
            server2=parts[0];
            port2 = Integer.parseInt(parts[1]);
        }
        username2 = args[5];
        password2 = args[6];
        file2 = args[7];

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

        try
        {
            int reply;
            if (port1 > 0) {
                ftp1.connect(server1, port1);
            } else {
                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;
            if (port2 > 0) {
                ftp2.connect(server2, port2);
            } else {
                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());

            // Although you would think the store command should be sent to server2
            // first, in reality, ftp servers like wu-ftpd start accepting data
            // connections right after entering passive mode.  Additionally, they
            // don't even send the positive preliminary reply until after the
            // transfer is completed (in the case of passive mode transfers).
            // Therefore, calling store first would hang waiting for a preliminary
            // reply.
            if (ftp1.remoteRetrieve(file1) && ftp2.remoteStoreUnique(file2))
            {
                //      if(ftp1.remoteRetrieve(file1) && ftp2.remoteStore(file2)) {
                // We have to fetch the positive completion reply.
                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
            }
        }
    }
}