这个小程序的实用性并不大，因为一般的浏览器都支持查看源代码，只是通过这个小程序巩固一下对Url，File，I/O等知识的掌握。
此程序在输入时不再需要加"http://"，直接输www形式的网站地址即可，保存时需要加所保存类型的后缀,如：.html，.txt，.doc等，推荐使用.html。
程序运行后效果：
输入网址后，按“确定”，则会显示出网页的源代码，再按保存，则可选择保存路径保存。
（此小程序运行正确的前提是所使用电脑能上网）
import java.awt.*; import java.awt.event.*; import java.io.*; import java.net.*; import javax.swing.*; public class UrlConnectionTest { public static void main(String[] args) { new TestFrame(); } } class TestFrame extends JFrame implements ActionListener, Runnable { byte[] b = new byte[118]; public TestFrame() { setVisible(true); setTitle("网页源代码获得器"); setSize(WIDTH, HEIGHT); button = new JButton("确定"); sButton = new JButton("保存"); text = new JTextField(15); area = new JTextArea(12, 12); button.addActionListener(this); sButton.addActionListener(this); thread = new Thread(); panel = new JPanel(); panel.add(new JLabel("输入网址：")); panel.add(text); panel.add(button); panel.add(sButton); Container con = this.getContentPane(); con.add(panel, BorderLayout.NORTH); con.add(new JScrollPane(area), BorderLayout.CENTER); saveFD = new FileDialog(this, "保存", FileDialog.SAVE); addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent e) { setVisible(false); System.exit(0); } }); } public void actionPerformed(ActionEvent e) { if ((!thread.isAlive())) { thread = new Thread(this); } try { thread.start(); } catch (Exception ee) { JOptionPane.showMessageDialog(this, "正在获取，请稍后", "提示信息", JOptionPane.ERROR_MESSAGE); } if (e.getSource() == sButton) { saveFD.setVisible(true); try { File f1 = new File(saveFD.getDirectory(), saveFD.getFile()); BufferedWriter bw = new BufferedWriter(new FileWriter(f1)); String gt = area.getText(); bw.write(gt, 0, gt.length()); bw.flush(); bw.close(); } catch (Exception e2) { e2.printStackTrace(); } } } public void run() { try { int n = -1; area.setText(null); url = new URL(("http://" + text.getText()).trim()); InputStream is = url.openStream(); while (-1 != (n = is.read(b, 0, b.length))) { String str = new String(b, 0, n); area.append(str); } } catch (MalformedURLException e1) { text.setText("" + e1); return; } catch (IOException e1) { text.setText("" + e1); return; } } public static final int WIDTH = 420; public static final int HEIGHT = 300; private URL url; private JButton button; private JButton sButton; private JTextField text; private JTextArea area; private Thread thread; private JPanel panel; private FileDialog saveFD; }