Java URL Download downloadFile(URL url, String name)

Description

Downloads an URL into a temporary file that is removed the next time the tempFileManager class is called, which means the next time gvSIG is launched.

License

Open Source License

Parameter

Parameter	Description
url	a parameter
name	a parameter

Exception

Parameter	Description
IOException	an exception
ServerErrorResponseException	an exception
ConnectException	an exception
UnknownHostException	an exception

Declaration

public static File downloadFile(URL url, String name)
        throws IOException, ConnectException, UnknownHostException

Method Source Code

//package com.java2s;
/* gvSIG. Sistema de Informaci?n Geogr?fica de la Generalitat Valenciana
 *
 * Copyright (C) 2004-2007 IVER T.I. and Generalitat Valenciana.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,USA.
 *
 * For more information, contact://from www.ja  v a  2 s .c  om
 *
 *  Generalitat Valenciana
 *   Conselleria d'Infraestructures i Transport
 *   Av. Blasco Ib??ez, 50
 *   46010 VALENCIA
 *   SPAIN
 *
 *      +34 963862235
 *   gvsig@gva.es
 *      www.gvsig.gva.es
 *
 *    or
 *
 *   IVER T.I. S.A
 *   Salamanca 50
 *   46005 Valencia
 *   Spain
 *
 *   +34 963163400
 *   dac@iver.es
 */

import java.io.BufferedOutputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

import java.net.ConnectException;

import java.net.URL;
import java.net.UnknownHostException;

import java.util.Hashtable;

public class Main {
    /**
      * <b>key</b>: URL, <b>value</b>: path to the downloaded file.
      */
    private static Hashtable downloadedFiles;
    public static final String TEMPDIRECTORYPATH = System.getProperty("java.io.tmpdir") + "/tmp-andami";

    /**
     * Downloads an URL into a temporary file that is removed the next time the
     * tempFileManager class is called, which means the next time gvSIG is launched.
     *
     * @param url
     * @param name
     * @return
     * @throws IOException
     * @throws ServerErrorResponseException
     * @throws ConnectException
     * @throws UnknownHostException
     */
    public static File downloadFile(URL url, String name)
            throws IOException, ConnectException, UnknownHostException {
        File f = null;

        try {
            if ((f = getPreviousDownloadedURL(url)) == null) {
                File tempDirectory = new File(TEMPDIRECTORYPATH);
                if (!tempDirectory.exists())
                    tempDirectory.mkdir();

                f = new File(TEMPDIRECTORYPATH + "/" + name + System.currentTimeMillis());

                System.out.println("downloading '" + url.toString() + "' to: " + f.getAbsolutePath());

                f.deleteOnExit();
                DataOutputStream dos = new DataOutputStream(new BufferedOutputStream(new FileOutputStream(f)));
                byte[] buffer = new byte[1024 * 256];
                InputStream is = url.openStream();
                long readed = 0;
                for (int i = is.read(buffer); i > 0; i = is.read(buffer)) {
                    dos.write(buffer, 0, i);
                    readed += i;
                }
                dos.close();
                addDownloadedURL(url, f.getAbsolutePath());
            }
        } catch (IOException io) {
            io.printStackTrace();
        }

        return f;
    }

    /**
     * Returns the content of this URL as a file from the file system.<br>
     * <p>
     * If the URL has been already downloaded in this session and notified
     * to the system using the static <b>Utilities.addDownloadedURL(URL)</b>
     * method, it can be restored faster from the file system avoiding to
     * download it again.
     * </p>
     * @param url
     * @return File containing this URL's content or null if no file was found.
     */
    private static File getPreviousDownloadedURL(URL url) {
        File f = null;
        if (downloadedFiles != null && downloadedFiles.containsKey(url)) {
            String filePath = (String) downloadedFiles.get(url);
            f = new File(filePath);
        }
        return f;
    }

    /**
     * Adds an URL to the table of downloaded files for further uses. If the URL
     * already exists in the table its filePath value is updated to the new one and
     * the old file itself is removed from the file system.
     *
     * @param url
     * @param filePath
     */
    private static void addDownloadedURL(URL url, String filePath) {
        if (downloadedFiles == null)
            downloadedFiles = new Hashtable();
        String fileName = (String) downloadedFiles.put(url, filePath);
        //JMV: No se puede eliminar el anterior porque puede que alguien lo
        // este usando
        /*
        if (fileName!=null){
        File f = new File(fileName);
        if (f.exists())
        f.delete();
        }
        */
    }
}

Java URL Download downloadFile(URL url, String name)

Description

License

Parameter

Exception

Declaration

Method Source Code

Related