1. final JButton button = new JButton("下载");  
2. button.addActionListener(new ActionListener() 
3. { 
4.     public void actionPerformed(ActionEvent e) 
5.     { 
6.         new Thread() 
7.         { 
8.             @Override 
9.             public void run() 
10.             { 
11.                 button.setEnabled(false);//设置按钮在下载过程中不可操作 
12.                 FileOutputStream fos = null; 
13.                 try 
14.                 { 
15.                     URL url = new URL(txtFilefjavaindexhtml.getText());//建立HTTP连接 
16.                     URLConnection conn = url.openConnection();//创建连接对象 
17.                      
18.                     int fileSize = conn.getContentLength();//用getContentLength()得到连接对象的文件大小 
19.                      
20.                     InputStream is = conn.getInputStream(); 
21.                     byte[] buffer = new byte[1024]; 
22.                     int length = 0; 
23.                      
24.                     fos = new FileOutputStream(txtFilefjavaindexhtml_1.getText()); 
25.                              
26.                     double downSize = 0; 
27.                     while (-1 != (length = is.read(buffer))) 
28.                     { 
29.                         downSize += length; 
30.                         double percent = downSize * 100 / fileSize;//计算下载百分比 
31.                         fos.write(buffer, 0, length); 
32.                         progressBar.setValue((int) percent);//设置进度条变化 
33.                     } 
34.                 } 
35.                 catch (MalformedURLException e1) 
36.                 { 
37.                     e1.printStackTrace(); 
38.                 } 
39.                 catch (IOException e1) 
40.                 { 
41.                     e1.printStackTrace(); 
42.                 } 
43.                 finally//输出流要记得在fanally关掉 
44.                 { 
45.                     button.setEnabled(true);//在finally中恢复按钮可操作 
46.                     if (null != fos) 
47.                     { 
48.                         try 
49.                         { 
50.                             fos.close(); 
51.                         } 
52.                         catch (IOException e1) 
53.                         { 
54.                             e1.printStackTrace(); 
55.                         } 
56.                     } 
57.                 } 
58.             } 
59.         }.start(); 
60.          
61.     } 
62. }); 
63. button.setFont(new Font("宋体", Font.PLAIN, 24)); 
64. button.setBounds(10, 164, 97, 37); 
65. frame.getContentPane().add(button); 
66.  
67. progressBar = new JProgressBar(); 
68. progressBar.setBounds(152, 164, 272, 37); 
69. frame.getContentPane().add(progressBar);//进度条按钮 

 

本文转自 glblong 51CTO博客，原文链接：http://blog.51cto.com/glblong/1186762，如需转载请自行联系原作者