DownloadHelper.java

/*
 * Jabox Open Source Version
 * Copyright (C) 2009-2010 Dimitris Kapanidis                                                                                                                          
 * 
 * This file is part of Jabox
 * 
 * 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 3 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, see http://www.gnu.org/licenses/.
 */
package org.jabox.utils;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class DownloadHelper {
    private static final Logger LOGGER = LoggerFactory
        .getLogger(DownloadHelper.class);

    /**
     * Downloads a remote file locally. If the file already exists then it
     * returns directly without downloading.
     * 
     * @param urlPath
     * @return
     */
    public static File downloadFile(final String urlPath,
            final File outputFile) {
        if (outputFile.exists()) {
            LOGGER.info(urlPath + " already exists at: " + outputFile);
            return outputFile;
        }

        LOGGER.info("Downloading: " + urlPath);
        InputStream is = null;
        BufferedInputStream bin = null;
        BufferedOutputStream bout = null;

        outputFile.getParentFile().mkdirs();

        try {
            URL url = new URL(urlPath);
            is = url.openStream();
            bin = new BufferedInputStream(is);
            bout =
                new BufferedOutputStream(new FileOutputStream(outputFile));
            while (true) {
                int datum = bin.read();
                if (datum == -1) {
                    break;
                }
                bout.write(datum);
            }
            bout.flush();
        } catch (IOException ioe) {
            ioe.printStackTrace();
        } finally {
            try {
                is.close();
                bin.close();
                bout.close();
            } catch (IOException ioe) {
                // nothing to see here
            }
        }
        return outputFile;
    }

}