geturl.java

java编程的一些Applets例子。值得深入研究一下。

// GetURL.java 



/*

 * Run this with: java GetURL dir URL [ URL ... ]

 * This program takes a list of URLs and copies the contents to files

 * with the same name as in the URL (minus the path); these files are

 * put in the directory 'dir'.

 * @author: Ronald Tschaler ([e-mail])

 */



import java.net.*;

import java.io.*;



class GetURL

{

    static final int buf_size = 4000;   // size of buffer used for copying



    public static void main (String args[])

    {

        int      idx,

                 tail,

                 numb,

                 dir_idx  = 0;

        boolean  noisy    = false;

        byte     buffer[] = new byte[buf_size];

        String   outfile;

        URL      url;



        InputStream      in;

        FileOutputStream out;



        /*** get command line options ***/



        while (dir_idx < args.length  &&  args[dir_idx].startsWith("-"))

        {

            if (args[0].equals("-noisy"))

            {

                noisy = true;

            }

            else

            {

                System.err.println("Unknown option: "+args[0]);

                return;

            }

            dir_idx++;

        }



        /*** check for correct number of command line arguments ***/



        if (args.length < dir_idx+2)

        {

            System.err.println("Usage: java GetURL [-noisy] directory URL "+

                               "[URL ...]");

            System.err.println("       copies the files specified by the "+

                               "URL's into directory");

            return;

        }



        /*** Get the files ***/



        for (idx=dir_idx+1; idx<args.length; idx++)

        {

            /*** Open URL ***/



            try

                url = new URL(args[idx]);

            catch (MalformedURLException e)

            {

                System.err.println("Error: malformed URL " + args[idx]);

                System.err.println(e.getMessage());

                continue;

            }



            try

                in = url.openStream();

            catch (IOException e)

            {

                System.err.println("Error: couldn't access " + args[idx]);

                System.err.println(e.getMessage());

                continue;

            }



            /*** extract filename and open file ***/



            tail    = args[idx].lastIndexOf('\\');

            if (tail == -1)

                tail = args[idx].lastIndexOf('/');

            outfile = args[idx].substring(tail + 1);



            try

                out = new FileOutputStream(args[dir_idx] + '/' + outfile);

            catch (IOException e)

            {

                System.err.println("Error: couldn't create " + args[dir_idx] +

                                  '/' + outfile);

                System.err.println(e.getMessage());

                continue;

            }



            /*** get the file ***/



            if (noisy)

                System.out.println("Copying "+outfile+"...");



            try

            {

                while ((numb = in.read(buffer)) != -1)

                    out.write(buffer, 0, numb);

            }

            catch (IOException e)

            {

                System.err.println("Error: IOException during copy");

                System.err.println(e.getMessage());

                continue;

            }



            /*** cleanup ***/



            try in.close();  catch (IOException e) { }

            try out.close(); catch (IOException e) { }

        }



        if (noisy)

            System.out.println("Done");



    }

}