一个工作示例，使用您的代码并在进度栏中显示进度，如下所示：
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://downloads.sourceforge.net/project/bitcoin/Bitcoin/blockchain/bitcoin_blockchain_170000.zip"); 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( "package.zip"); 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() { jProgressBar.setValue(currentProgress); } }); bout.write(data, 0, x); } bout.close(); in.close(); } catch (FileNotFoundException e) { } catch (IOException e) { } } }; new Thread(updatethread). start(); }}这显示了如何做-在使用它之前，您应该考虑GUI-Threads等。
