按照书上敲了个简单实现WebBrowser的代码，运行结果，网站总是在变化
代码如下
package ex30;import java.awt.*;import java.awt.event.*;import javax.swing.*;import java.net.URL;import javax.swing.event.*;import java.io.*;public class WebBrowser extends JApplet{ // JEditor pane to view HTML files private JEditorPane jep = new JEditorPane(); // Label for URL private JLabel jlblURL = new JLabel("URL"); // Text field for entering URL private JTextField jtfURL = new JTextField(); /** Initialize the applet */ public void init(){ // Create a panel jpURL to hold the label and text field JPanel jpURL = new JPanel(); jpURL.setLayout(new BorderLayout()); jpURL.add(jlblURL, BorderLayout.WEST); jpURL.add(jtfURL, BorderLayout.CENTER); // Place jpURL and jspViewer in the applet add(new JScrollPane(jep), BorderLayout.CENTER); add(jpURL, BorderLayout.NORTH); // Set jep noneditable jep.setEditable(false); // Register listener jep.addHyperlinkListener(new HyperlinkListener(){ public void hyperlinkUpdate(HyperlinkEvent e){ try{ jep.setPage(e.getURL()); } catch(IOException ex){ System.out.println(ex); } } }); jtfURL.addActionListener(new ActionListener(){ public void actionPerformed(ActionEvent e){ try{ // Get the URL from text field URL url = new URL(jtfURL.getText().trim()); // Display the HTML file jep.setPage(url); } catch(IOException ex){ System.out.println(ex); } } }); }}