webbrowser.java

java Applet应用程序

// WebBrowser.java: Display HTML file in JEditorPane
import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import javax.swing.*;
import java.net.URL;
import javax.swing.event.*;
import java.io.*;

public class WebBrowser extends JApplet
  implements ActionListener, HyperlinkListener
{
  // JEditor pane to view HTML files
  JEditorPane jep = new JEditorPane();

  // Label for URL
  JLabel jlblURL = new JLabel("URL");

  // Text field for entering URL
  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);

    // Create a scroll pane to hold JEditorPane
    JScrollPane jspViewer = new JScrollPane();
    jspViewer.getViewport().add(jep, null);

    // Place jpURL and jspViewer in the applet
    this.getContentPane().add(jspViewer, BorderLayout.CENTER);
    this.getContentPane().add(jpURL, BorderLayout.NORTH);

    // Set jep noneditable
    jep.setEditable(false);

    // Register listener
    jep.addHyperlinkListener(this);
    jtfURL.addActionListener(this);
  }

  public void actionPerformed(ActionEvent e)
  {
    // TODO: Implement this java.awt.event.ActionListener method
    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);
    }
  }

  public void hyperlinkUpdate(HyperlinkEvent e)
  {
    // TODO: Implement HyperlinkListener method
    try
    {
      jep.setPage(e.getURL());
    }
    catch (IOException ex)
    {
      System.out.println(ex);
    }
  }

  // Main method
  public static void main(String[] args)
  {
    // Create a frame
    JFrame frame = new JFrame("Web Browser");

    // Create an instance of the applet
    WebBrowser applet = new WebBrowser();

    // Add the applet instance to the frame
    frame.getContentPane().add(applet, BorderLayout.CENTER);

    // Invoke init() and start()
    applet.init();
    applet.start();

    // Display the frame
    frame.setSize(600, 600);
    // frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setVisible(true);
  }
}