我正在用java做一个非常简单的项目，试图理解如何使用keylistener。我创建了一个主类和一个keylister，mouselistener类。当我按键盘键时，我想让事情发生。到目前为止，唯一有效的是“你好”当我点击。
这是我的密码：

import javax.swing.JFrame;
import javax.swing.JPanel;

public class KeyPractice{

    public static void main(String[] args) {

        JFrame frame = new JFrame();
        JPanel panel = new JPanel();

        panel.addKeyListener(new KeyEar());
        panel.addMouseListener(new KeyEar());

        frame.add(panel);

        frame.setVisible(true);
        frame.setSize(400, 400);
    } 
}

还有keylistener类。。。。

import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;

public class KeyEar implements KeyListener, MouseListener {

    public KeyEar(){

    }

    @Override
    public void mouseClicked(MouseEvent arg0) {
        System.out.println("Hello");
    }

    @Override
    public void mouseEntered(MouseEvent arg0) {
        // TODO Auto-generated method stub
    }

    @Override
    public void mouseExited(MouseEvent arg0) {
        // TODO Auto-generated method stub
    }

    @Override
    public void mousePressed(MouseEvent arg0) {
        // TODO Auto-generated method stub
    }

    @Override
    public void mouseReleased(MouseEvent arg0) {
        // TODO Auto-generated method stub
    }

    @Override
    public void keyPressed(KeyEvent arg0) {
        System.out.println("Hello");
    }

    @Override
    public void keyReleased(KeyEvent arg0) {
        System.out.println("Hello");
    }

    @Override
    public void keyTyped(KeyEvent arg0) {
        System.out.println("Hello");
    }
}