Commons Net example source code file (TFTPExample.java)

This example Commons Net source code file (TFTPExample.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

error, file, fileinputstream, fileinputstream, fileoutputstream, i/o, i/o, io, ioexception, ioexception, net, network, string, tftpclient, the, the, unknownhostexception

The Commons Net TFTPExample.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.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.SocketException;
import java.net.UnknownHostException;
import org.apache.commons.net.tftp.TFTP;
import org.apache.commons.net.tftp.TFTPClient;

/***
 * This is an example of a simple Java tftp client using NetComponents.
 * Notice how all of the code is really just argument processing and
 * error handling.
 * <p>
 * Usage: tftp [options] hostname localfile remotefile
 * hostname   - The name of the remote host
 * localfile  - The name of the local file to send or the name to use for
 *              the received file
 * remotefile - The name of the remote file to receive or the name for
 *              the remote server to use to name the local file being sent.
 * options: (The default is to assume -r -b)
 *        -s Send a local file
 *        -r Receive a remote file
 *        -a Use ASCII transfer mode
 *        -b Use binary transfer mode
 * <p>
 ***/
public final class TFTPExample
{
    static final String USAGE =
        "Usage: tftp [options] hostname localfile remotefile\n\n" +
        "hostname   - The name of the remote host\n" +
        "localfile  - The name of the local file to send or the name to use for\n" +
        "\tthe received file\n" +
        "remotefile - The name of the remote file to receive or the name for\n" +
        "\tthe remote server to use to name the local file being sent.\n\n" +
        "options: (The default is to assume -r -b)\n" +
        "\t-s Send a local file\n" +
        "\t-r Receive a remote file\n" +
        "\t-a Use ASCII transfer mode\n" +
        "\t-b Use binary transfer mode\n";

    public final static void main(String[] args)
    {
        boolean receiveFile = true, closed;
        int transferMode = TFTP.BINARY_MODE, argc;
        String arg, hostname, localFilename, remoteFilename;
        TFTPClient tftp;

        // Parse options
        for (argc = 0; argc < args.length; argc++)
        {
            arg = args[argc];
            if (arg.startsWith("-"))
            {
                if (arg.equals("-r"))
                    receiveFile = true;
                else if (arg.equals("-s"))
                    receiveFile = false;
                else if (arg.equals("-a"))
                    transferMode = TFTP.ASCII_MODE;
                else if (arg.equals("-b"))
                    transferMode = TFTP.BINARY_MODE;
                else
                {
                    System.err.println("Error: unrecognized option.");
                    System.err.print(USAGE);
                    System.exit(1);
                }
            }
            else
                break;
        }

        // Make sure there are enough arguments
        if (args.length - argc != 3)
        {
            System.err.println("Error: invalid number of arguments.");
            System.err.print(USAGE);
            System.exit(1);
        }

        // Get host and file arguments
        hostname = args[argc];
        localFilename = args[argc + 1];
        remoteFilename = args[argc + 2];

        // Create our TFTP instance to handle the file transfer.
        tftp = new TFTPClient();

        // We want to timeout if a response takes longer than 60 seconds
        tftp.setDefaultTimeout(60000);

        // Open local socket
        try
        {
            tftp.open();
        }
        catch (SocketException e)
        {
            System.err.println("Error: could not open local UDP socket.");
            System.err.println(e.getMessage());
            System.exit(1);
        }

        // We haven't closed the local file yet.
        closed = false;

        // If we're receiving a file, receive, otherwise send.
        if (receiveFile)
        {
            FileOutputStream output = null;
            File file;

            file = new File(localFilename);

            // If file exists, don't overwrite it.
            if (file.exists())
            {
                System.err.println("Error: " + localFilename + " already exists.");
                System.exit(1);
            }

            // Try to open local file for writing
            try
            {
                output = new FileOutputStream(file);
            }
            catch (IOException e)
            {
                tftp.close();
                System.err.println("Error: could not open local file for writing.");
                System.err.println(e.getMessage());
                System.exit(1);
            }

            // Try to receive remote file via TFTP
            try
            {
                tftp.receiveFile(remoteFilename, transferMode, output, hostname);
            }
            catch (UnknownHostException e)
            {
                System.err.println("Error: could not resolve hostname.");
                System.err.println(e.getMessage());
                System.exit(1);
            }
            catch (IOException e)
            {
                System.err.println(
                    "Error: I/O exception occurred while receiving file.");
                System.err.println(e.getMessage());
                System.exit(1);
            }
            finally
            {
                // Close local socket and output file
                tftp.close();
                try
                {
                    if (output != null) {
                        output.close();
                    }
                    closed = true;
                }
                catch (IOException e)
                {
                    closed = false;
                    System.err.println("Error: error closing file.");
                    System.err.println(e.getMessage());
                }
            }

            if (!closed)
                System.exit(1);

        }
        else
        {
            // We're sending a file
            FileInputStream input = null;

            // Try to open local file for reading
            try
            {
                input = new FileInputStream(localFilename);
            }
            catch (IOException e)
            {
                tftp.close();
                System.err.println("Error: could not open local file for reading.");
                System.err.println(e.getMessage());
                System.exit(1);
            }

            // Try to send local file via TFTP
            try
            {
                tftp.sendFile(remoteFilename, transferMode, input, hostname);
            }
            catch (UnknownHostException e)
            {
                System.err.println("Error: could not resolve hostname.");
                System.err.println(e.getMessage());
                System.exit(1);
            }
            catch (IOException e)
            {
                System.err.println(
                    "Error: I/O exception occurred while sending file.");
                System.err.println(e.getMessage());
                System.exit(1);
            }
            finally
            {
                // Close local socket and input file
                tftp.close();
                try
                {
                    if (input != null) {
                        input.close();
                    }
                    closed = true;
                }
                catch (IOException e)
                {
                    closed = false;
                    System.err.println("Error: error closing file.");
                    System.err.println(e.getMessage());
                }
            }

            if (!closed)
                System.exit(1);

        }

    }

}