/* * Copyright (c) 2000 David Flanagan.  All rights reserved. * This code is from the book Java Examples in a Nutshell, 2nd Edition. * It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied. * You may study, use, and modify it for any non-commercial purpose. * You may distribute it non-commercially as long as you retain this notice. * For a commercial use license, or to purchase the book (recommended), * visit http://www.davidflanagan.com/javaexamples2. */package com.davidflanagan.examples.net;import java.io.*;import java.net.*;/** * This simple program uses the URL class and its openStream() method to * download the contents of a URL and copy them to a file or to the console. **/public class GetURL {    public static void main(String[] args) {        InputStream in = null;           OutputStream out = null;        try {            // Check the arguments            if ((args.length != 1)&& (args.length != 2))                 throw new IllegalArgumentException("Wrong number of args");	                // Set up the streams            URL url = new URL(args[0]);   // Create the URL            in = url.openStream();        // Open a stream to it            if (args.length == 2)         // Get an appropriate output stream                out = new FileOutputStream(args[1]);            else out = System.out;	                // Now copy bytes from the URL to the output stream            byte[] buffer = new byte[4096];            int bytes_read;            while((bytes_read = in.read(buffer)) != -1)                out.write(buffer, 0, bytes_read);	}        // On exceptions, print error message and usage message.        catch (Exception e) {            System.err.println(e);            System.err.println("Usage: java GetURL <URL> [<filename>]");        }        finally {  // Always close the streams, no matter what.            try { in.close();  out.close(); } catch (Exception e) {}        }    }}