java - 进度条和下载

Question

下面的代码完全符合我的需要。我只需要让这个下载更多不同的URL（图片），遗憾的是我不知道该怎么做。如果有人能帮助我解决这个问题，我会非常感激。

import java.io.BufferedOutputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;

import javax.swing.JFrame;
import javax.swing.JProgressBar;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;

public class Progressbar {

  public static void main(String[] args) {

    final JProgressBar jProgressBar = new JProgressBar();
    jProgressBar.setMaximum(100000);
    JFrame frame = new JFrame();
    frame.setContentPane(jProgressBar);
    frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    frame.setSize(300, 70);
    frame.setVisible(true);
    Runnable updatethread = new Runnable() {
      public void run() {
        try {
          URL url = new URL("http://www.drgarbage.com/img/howto/cfgf-tutorial/createcfg.png");
          HttpURLConnection httpConnection = (HttpURLConnection) (url.openConnection());                        
          long completeFileSize = httpConnection.getContentLength();
          java.io.BufferedInputStream in = new     java.io.BufferedInputStream(httpConnection.getInputStream());
          java.io.FileOutputStream fos = new java.io.FileOutputStream("picture.png");
          java.io.BufferedOutputStream bout = new BufferedOutputStream(fos, 1024);                       
          byte[] data = new byte[1024];
          long downloadedFileSize = 0;
          int x = 0;
          while ((x = in.read(data, 0, 1024)) >= 0) { 
            downloadedFileSize += x;

            // calculate progress
            final int currentProgress = (int) ((((double)downloadedFileSize) / ((double)completeFileSize)) * 100000d);

            // update progress bar
            SwingUtilities.invokeLater(new Runnable() {

              @Override
              public void run() {
                ProgressBar.setValue(currentProgress);
              }
            });
            bout.write(data, 0, x);
          }
          bout.close();
          in.close();
        } catch (FileNotFoundException e) {
        } catch (IOException e) {
        }
      }
    };
    new Thread(updatethread).

    start();
  }
}