?? urltest.java
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//Listing 21-1 -- URLTest.java
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.*;
import java.net.*;
public class URLTest extends Applet implements ActionListener {
private URL url_site; // URL for connection
// Add buttons
private Button bu_microsoft = new Button("Microsoft");
private Button bu_sun = new Button("Sun");
private Button bu_connect = new Button("Connect");
// Add text fields
private Label lbl_file;
private Label lbl_host;
private Label lbl_port;
private Label lbl_protocol;
private Label lbl_ref;
private Label lbl_externalForm;
private Label lbl_string;
public void init() { // init called when applet starts
Panel northPanel = new Panel();
Panel centerPanel = new Panel();
Panel fieldPanel = new Panel();
Panel labelPanel = new Panel();
Panel southPanel = new Panel();
// Set Panel and Applet layouts
setLayout(new BorderLayout());
centerPanel.setLayout(new BorderLayout());
labelPanel.setLayout(new GridLayout(7,1));
fieldPanel.setLayout(new GridLayout(7,1));
northPanel.setLayout(new FlowLayout());
southPanel.setLayout(new FlowLayout());
//Add buttons to the appropriate Panels
northPanel.add(bu_microsoft);
northPanel.add(bu_sun);
southPanel.add(bu_connect);
//Add labels to the labelPanel
labelPanel.add(new Label("File Name: ", Label.RIGHT));
labelPanel.add(new Label("Host: ", Label.RIGHT));
labelPanel.add(new Label("Port: ", Label.RIGHT));
labelPanel.add(new Label("Protocol: ", Label.RIGHT));
labelPanel.add(new Label("Reference: ", Label.RIGHT));
labelPanel.add(new Label("External Form: ", Label.RIGHT));
labelPanel.add(new Label("String: ", Label.RIGHT));
//Add label "fields" to the fieldPanel
fieldPanel.add(lbl_file = new Label());
fieldPanel.add(lbl_host = new Label());
fieldPanel.add(lbl_port = new Label());
fieldPanel.add(lbl_protocol = new Label());
fieldPanel.add(lbl_ref = new Label());
fieldPanel.add(lbl_externalForm = new Label());
fieldPanel.add(lbl_string = new Label());
//Add ActionListeners for all buttons
bu_connect.addActionListener(this);
bu_microsoft.addActionListener(this);
bu_sun.addActionListener(this);
//Arrange Panels
centerPanel.add("West", labelPanel);
centerPanel.add("Center", fieldPanel);
add("North", northPanel);
add("South", southPanel);
add("Center", centerPanel);
}
public void showWeb(String s) { //Gets a new URL from a string
try {
url_site = null; //Force garbage collection
url_site = new URL(s); //Define a new URL
webInfo(); //Call webInfo method
}
catch (MalformedURLException mue) {
showStatus ("A MalformedURLException has occurred");
url_site = null;
}
}
public void webInfo() { //Displays the web info
lbl_file.setText(url_site.getFile()); // URL file name
lbl_host.setText(url_site.getHost()); // URL host name
lbl_port.setText(String.valueOf(url_site.getPort())); // URL port
lbl_protocol.setText(url_site.getProtocol()); // URL protocol
lbl_ref.setText(url_site.getRef()); // URL reference
lbl_externalForm.setText(url_site.toExternalForm()); // URL external form
lbl_string.setText(url_site.toString()); // URL string
}
//The actionPerformed method is required
//by the ActionListener interface
public void actionPerformed(ActionEvent e) {
// Get the text of the button
String buttonText = e.getActionCommand();
//Test for buttons
if (buttonText.equals("Microsoft")) {
showWeb("http://www.microsoft.com/visualj");
}
else if (buttonText.equals("Sun")) {
showWeb("http://www.sun.com/java");
}
else if (buttonText.equals("Connect")) {
showStatus("Connecting to web site...Please wait.");
getAppletContext().showDocument(url_site); //Connect to the URL
showStatus("");
}
}
}
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