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;