使用Swing中的JOptionPane类

实现代码：

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class TestSwing extends JFrame {

    public TestSwing() {
        this.setDefaultCloseOperation(WindowConstants.DO_NOTHING_ON_CLOSE);
        JOptionPane.showMessageDialog(null, "程序开始运行");
        JScrollPane sp = new JScrollPane();
        JTextArea ta = new JTextArea(100, 50);
        sp.getViewport().add(ta);
        this.getContentPane().add(sp);
        addWindowListener(new WindowAdapter() {
            public void windowClosing(WindowEvent e) {
                if (JOptionPane.OK_OPTION == JOptionPane.showConfirmDialog(
                        TestSwing.this, "真的要退出吗？", "结束程序",
                        JOptionPane.YES_NO_CANCEL_OPTION,
                        JOptionPane.QUESTION_MESSAGE)) {
                    dispose();
                    System.exit(0);
                }
            }
        });

    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        System.out.println("Starting TestMyButton...");
        TestSwing mainFrame = new TestSwing();
        mainFrame.setSize(400, 400);
        mainFrame.setTitle("TestButton");
        mainFrame.setVisible(true);
    }

}

程序开始运行时：

运行中：

单击退出按钮：