Dowloader.java

package com.huantt.downloader;

import java.io.*;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

/**
 * Created by Huan on 7/5/2016.
 */
public class Downloader implements Runnable {
    private static org.apache.log4j.Logger log = org.apache.log4j.Logger.getLogger(Downloader.class);
    private BufferedInputStream bis;
    private BufferedOutputStream bos;
    private String link;
    private String path;
    private String fileName;

    public Downloader(String link, String path, String fileName) {
        this.link = link;
        this.path = path;
        fileName += getFormatFile();
    }

    public Downloader(String link, String path) {
        this.link = link;
        this.path = path;
        this.fileName = getFileName();
    }

    private String getFileName() {
        return new String(link.substring(link.lastIndexOf('/') + 1));
    }

    private String getFormatFile() {
        String format = "";
        if (link.lastIndexOf(".") != -1) {
            format = link.substring(link.lastIndexOf("."));
        }
        return format;
    }

    @Override
    public void run() {
        URL url = null;
        try {
            url = new URL(link);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            bis = new BufferedInputStream(connection.getInputStream());
            File file = new File(path + "/" + fileName);
            bos = new BufferedOutputStream(new FileOutputStream(file));
        } catch (MalformedURLException e) {
          log.error(e.toString());
        } catch (IOException e) {
          log.error(e.toString());
        }
        byte[] bytes = new byte[1024];
        int length;
        try {
            while ((length = bis.read(bytes)) != -1) {
                bos.write(bytes, 0, length);
            }
            bos.close();
            log.info("Finish !");
        } catch (IOException e) {
           log.error(e.toString());
        }

    }
}