下载器-http 进度条 文件读写

 

 

 

final JButton button = new JButton("下载");
button.addActionListener(new ActionListener()
{
    public void actionPerformed(ActionEvent e)
    {
        new Thread()
        {
            @Override
            public void run()
            {
                button.setEnabled(false);//设置按钮在下载过程中不可操作
                FileOutputStream fos = null;
                try
                {
                    URL url = new URL(txtFilefjavaindexhtml.getText());//建立HTTP连接
                    URLConnection conn = url.openConnection();//创建连接对象

                    int fileSize = conn.getContentLength();//用getContentLength()得到连接对象的文件大小

                    InputStream is = conn.getInputStream();
                    byte[] buffer = new byte[1024];
                    int length = 0;

                    fos = new FileOutputStream(txtFilefjavaindexhtml_1.getText());

                    double downSize = 0;
                    while (-1 != (length = is.read(buffer)))
                    {
                        downSize += length;
                        double percent = downSize * 100 / fileSize;//计算下载百分比
                        fos.write(buffer, 0, length);
                        progressBar.setValue((int) percent);//设置进度条变化
                    }
                }
                catch (MalformedURLException e1)
                {
                    e1.printStackTrace();
                }
                catch (IOException e1)
                {
                    e1.printStackTrace();
                }
                finally//输出流要记得在fanally关掉
                {
                    button.setEnabled(true);//在finally中恢复按钮可操作
                    if (null != fos)
                    {
                        try
                        {
                            fos.close();
                        }
                        catch (IOException e1)
                        {
                            e1.printStackTrace();
                        }
                    }
                }
            }
        }.start();

    }
});
button.setFont(new Font("宋体", Font.PLAIN, 24));
button.setBounds(10, 164, 97, 37);
frame.getContentPane().add(button);

progressBar = new JProgressBar();
progressBar.setBounds(152, 164, 272, 37);
frame.getContentPane().add(progressBar);//进度条按钮

 

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