问答题

本题的功能是监听键盘敲击事件，并将敲击的字符显示在标签上。开始，文字标签提示“Please press your keyboard!”，当按下键盘上的字符键，文字标签就变为“’*’is pressed!”(*为所按字母)。
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class java2 extends Frame______
public static void main(String args[])
java2 f=new java2("java2");
Panel pan=new Panel();
f.init();
public java2(String str)
super(str);
public void init()
addWindowListener(new WindowAdapter()
public void windowClosing(WindowEvent e)
System.exit(0);
);
setSize(200,200);
setLayout(new FlowLayout());
lab=new Label("Please press your keyboard!");
add(lab);
addKeyListener(this);
setVisible(true);
public void keyTyped(KeyEvent e)
lab.setText("\’"+______+"\’is pressed!");
repaint();
public void keyPressed(KeyEvent e)
public void keyReleased(KeyEvent e)
private Label lab;