《Java2图形设计卷II：Swing》配套光盘源码

				import java.awt.*;
				import java.awt.event.*;
				import javax.swing.*;
				
				public class Test extends JApplet {
					private JButton button = new JButton("show dialog ...");
				
					private String title = "dialog title";
					private String message = "information";
					private int messageType = JOptionPane.INFORMATION_MESSAGE;
					private String messages[] = {
						"information", "error", "warning", "question", "plain"
					};
				
					public Test() {
						Container contentPane = getContentPane();
						JPanel controlPanel = new ControlPanel(this);
				
						contentPane.setLayout(new FlowLayout());
						contentPane.add(controlPanel);
						contentPane.add(button);
				
						button.addActionListener(new ActionListener() {
							public void actionPerformed(ActionEvent e) {
								JOptionPane.showMessageDialog(
								  button, // parentComponent
								  message, // message
								  title, // title
								  messageType);
							}
						});
					}
					public void setMessageType(int messageType) {
						this.messageType = messageType;
				
						switch(messageType) {
							case JOptionPane.INFORMATION_MESSAGE:
									message = messages[0]; 
									break;
							case JOptionPane.ERROR_MESSAGE:
									message = messages[1]; 
									break;
							case JOptionPane.WARNING_MESSAGE:
									message = messages[2]; 
									break;
							case JOptionPane.QUESTION_MESSAGE:
									message = messages[3]; 
									break;
							case JOptionPane.PLAIN_MESSAGE:
									message = messages[4]; 
									break;
						}
					}
				}
				class ControlPanel extends JPanel { 
					private JComboBox messageTypes = new JComboBox();
					private int[] typeValues = {
						JOptionPane.INFORMATION_MESSAGE,
						JOptionPane.ERROR_MESSAGE,
						JOptionPane.WARNING_MESSAGE,
						JOptionPane.QUESTION_MESSAGE,
						JOptionPane.PLAIN_MESSAGE,
					};
					private String[] typeNames = {
						"JOptionPane.INFORMATION_MESSAGE",
						"JOptionPane.ERROR_MESSAGE",
						"JOptionPane.WARNING_MESSAGE",
						"JOptionPane.QUESTION_MESSAGE",
						"JOptionPane.PLAIN_MESSAGE",
					};
				
					public ControlPanel(final Test applet) {
						add(messageTypes);
				
						for(int i=0; i < typeNames.length; ++i) {
							messageTypes.addItem(typeNames[i]);
						}
						messageTypes.addItemListener(new ItemListener() {
							public void itemStateChanged(ItemEvent e) {
								String s = (String)messageTypes.getSelectedItem();
								int type;
				
								for(int i=0; i < typeNames.length; ++i) {
									if(s.equals(typeNames[i]))
										applet.setMessageType(typeValues[i]);
								}
							}
						});
					}
				}