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