Java tutorial
/* * 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. */ 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. * 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 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); } } } }