Java example source code file (FTPSExample.java)

This example source code file (FTPSExample.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 tags/keywords

ascii, fileinputstream, fileoutputstream, ftpconnectionclosedexception, ftpsclient, ftpsexample, io, ioexception, nosuchalgorithmexception, printcommandlistener, security, ssl/tls, string, usage

The FTPSExample.java example 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.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.security.NoSuchAlgorithmException;

import org.apache.commons.net.PrintCommandListener;
import org.apache.commons.net.ftp.FTP;
import org.apache.commons.net.ftp.FTPConnectionClosedException;
import org.apache.commons.net.ftp.FTPReply;
import org.apache.commons.net.ftp.FTPSClient;

/***
 * This is an example program demonstrating how to use the FTPSClient class.
 * This program connects to an FTP server and retrieves the specified
 * file.  If the -s flag is used, it stores the local file at the FTP server.
 * Just so you can see what's happening, all reply strings are printed.
 * If the -b flag is used, a binary transfer is assumed (default is ASCII).
 * <p>
 * Usage: ftp [-s] [-b] <hostname>    
 * <p>
 ***/
public final class FTPSExample
{

    public static final String USAGE =
        "Usage: ftp [-s] [-b] <hostname>    \n" +
        "\nDefault behavior is to download a file and use ASCII transfer mode.\n" +
        "\t-s store file on server (upload)\n" +
        "\t-b use binary transfer mode\n";

    public static final void main(String[] args) throws NoSuchAlgorithmException
    {
        int base = 0;
        boolean storeFile = false, binaryTransfer = false, error = false;
        String server, username, password, remote, local;
        String protocol = "SSL";    // SSL/TLS
        FTPSClient ftps;
        
        for (base = 0; base < args.length; base++)
        {
            if (args[base].startsWith("-s"))
                storeFile = true;
            else if (args[base].startsWith("-b"))
                binaryTransfer = true;
            else
                break;
        }

        if ((args.length - base) != 5)
        {
            System.err.println(USAGE);
            System.exit(1);
        }

        server = args[base++];
        username = args[base++];
        password = args[base++];
        remote = args[base++];
        local = args[base];

        ftps = new FTPSClient(protocol);
       
        ftps.addProtocolCommandListener(new PrintCommandListener(new PrintWriter(System.out)));

        try
        {
            int reply;

            ftps.connect(server);
            System.out.println("Connected to " + server + ".");

            // After connection attempt, you should check the reply code to verify
            // success.
            reply = ftps.getReplyCode();

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

__main:
        try
        {
            ftps.setBufferSize(1000);

            if (!ftps.login(username, password))
            {
                ftps.logout();
                error = true;
                break __main;
            }

            
            System.out.println("Remote system is " + ftps.getSystemName());

            if (binaryTransfer) ftps.setFileType(FTP.BINARY_FILE_TYPE);

            // Use passive mode as default because most of us are
            // behind firewalls these days.
            ftps.enterLocalPassiveMode();

            if (storeFile)
            {
                InputStream input;

                input = new FileInputStream(local);

                ftps.storeFile(remote, input);

                input.close();
            }
            else
            {
                OutputStream output;

                output = new FileOutputStream(local);

                ftps.retrieveFile(remote, output);

                output.close();
            }

            ftps.logout();
        }
        catch (FTPConnectionClosedException e)
        {
            error = true;
            System.err.println("Server closed connection.");
            e.printStackTrace();
        }
        catch (IOException e)
        {
            error = true;
            e.printStackTrace();
        }
        finally
        {
            if (ftps.isConnected())
            {
                try
                {
                    ftps.disconnect();
                }
                catch (IOException f)
                {
                    // do nothing
                }
            }
        }

        System.exit(error ? 1 : 0);
    } // end main

}