首先，每个人都需要知道我对Java编码还比较陌生。更准确地说，我是面向对象编程的新手。

问题。

我试图创建一个下载类来更新进度条，以显示其进度。可能还有其他决定，我决定在以后进行更新。

目前的问题是，在我看来，这不起作用。我可以在“主要”方法上做任何我想做的事情，而且GUI仍然响应迅速。根据我过去的编程经验，除非我对GUI进行线程化，否则这是不可能的。为什么是这样？

既然可以了，这样可以吗？

主班

package atomicElectronics;

import java.io.IOException;

import atomicElectronics.physical.AtomFrame;
import atomicElectronics.utility.Download;

public class Initial {

    static AtomFrame atomLauncher;

    public static void main(String[] args) {

        atomLauncher = new AtomFrame();
        atomLauncher.start();

        System.out.println(Integer.MAX_VALUE);

        Download theDownload = new Download();
        theDownload.fileProgressBar(atomLauncher.progressBar);
        try {
            theDownload.exicute("http://download.videolan.org/pub/videolan/vlc/last/win64/vlc-2.1.3-win64.exe", "C:\\Users\\TrinaryAtom\\AppData\\Roaming");
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        // TODO Add Download Methods
        // theDownload.updateBarTotal(JProgressBar);
        // theDownload.updateLabelSpeed(String);
        // theDownload.updateLabelTotal(String);
        // theDownload.addFile(File);
        // theDownload.addFiles(Files);
    }

}

类AtomFrame

package atomicElectronics.physical;

import javax.swing.JFrame;
import java.awt.FlowLayout;
import javax.swing.JProgressBar;

public class AtomFrame extends JFrame{

    public JProgressBar progressBar;

    private static final long serialVersionUID = 4010489530693307355L;

    public static void main(String[] args){
        AtomFrame testFrame = new AtomFrame();
        testFrame.start();
    }

    public AtomFrame(){
        initializeComponents();
    }

    public void initializeComponents(){
        this.setSize(400, 400);
        this.setLocationRelativeTo(null);
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setTitle("Atom Launcher");
        this.setLayout(new FlowLayout(FlowLayout.CENTER, 5, 5));

        progressBar = new JProgressBar();
        this.add(progressBar);

        //this.pack();
    }

    public void start() {
        this.setVisible(true);
    }

    public void close() {
        this.dispose();
    }
}

类下载

package atomicElectronics.utility;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;

import javax.swing.JProgressBar;

public class Download {

    private static final int BUFFER_SIZE = 4096;
    private JProgressBar fileProgressBar;

    public Download() {
    }

    public void fileProgressBar(JProgressBar fileBar) {
        fileProgressBar = fileBar;
    }

    public void exicute(String fileURL, String saveDir) throws IOException  {

        URL url = new URL(fileURL);
        HttpURLConnection httpConn = (HttpURLConnection) url.openConnection();
        int responseCode = httpConn.getResponseCode();

        // always check HTTP response code first
        if (responseCode == HttpURLConnection.HTTP_OK) {
            String fileName = "";
            String disposition = httpConn.getHeaderField("Content-Disposition");
            String contentType = httpConn.getContentType();
            double contentLength = httpConn.getContentLength();

            if (disposition != null) {
                // extracts file name from header field
                int index = disposition.indexOf("filename=");
                if (index > 0) {


          fileName = disposition.substring(index + 9,
                        disposition.length());
            }
        } else {
            // extracts file name from URL
            fileName = fileURL.substring(fileURL.lastIndexOf("/") + 1,
                    fileURL.length());
        }

        System.out.println("Content-Type = " + contentType);
        System.out.println("Content-Disposition = " + disposition);
        System.out.println("Content-Length = " + contentLength);
        System.out.println("fileName = " + fileName);

        // opens input stream from the HTTP connection
        InputStream inputStream = httpConn.getInputStream();
        String saveFilePath = saveDir + File.separator + fileName;

        // opens an output stream to save into file
        FileOutputStream outputStream = new FileOutputStream(saveFilePath);

        double totalRead = 0;
        int bytesRead = -1;
        byte[] buffer = new byte[BUFFER_SIZE];
        while ((bytesRead = inputStream.read(buffer)) != -1) {
            outputStream.write(buffer, 0, bytesRead);
            totalRead += bytesRead;
            System.out.println((totalRead / contentLength) * 100);
            fileProgressBar.setValue((int)((totalRead / contentLength) * 100));
        }

        outputStream.close();
        inputStream.close();

        System.out.println("File downloaded");
    } else {
        System.out.println("No file to download. Server replied HTTP code: " + responseCode);
    }
    httpConn.disconnect();

}

}