Eclipse Java KeyEvent.VK_LEFT（不工作）

Question

这是一些代码，应该创建一个可以通过箭头键控制的椭圆形，我已经做了很多研究但是我找不到解决问题的方法。我正在使用Eclipse Mars和Java语言。这是我的代码。

package com.game;

import java.applet.Applet;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;



public class Game extends Applet implements KeyListener, Runnable {

public int x,y;
public boolean up,down,left,right;
public Image offscreen;
public Graphics d;





public void init(){
    setSize(854,480);
    Thread th = new Thread(this);
    th.start();
    offscreen = createImage(854,480);
    d = offscreen.getGraphics();
    this.addKeyListener(new Game());




}
public void run(){

    while(true)
    {

        System.out.println("X: " + x);
        System.out.println("Y: " + y);
        if(left == true){
            x--;
        }
        if(right == true){
            x++;
        }

        if(up == true){
            y--;
        }
        if(down == true){
            y++;
        }
        repaint();
        try {
            Thread.sleep(20);
        } catch (InterruptedException e) {

            e.printStackTrace();
        }
    }

}
public void keyTyped(KeyEvent e) {
    if (e.getKeyCode() == KeyEvent.VK_LEFT) {
        left = true;
        System.out.println("Left key pressed");
        }
    if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
        right = true;
        System.out.println("Right key pressed");
        }

}

public void keyPressed(KeyEvent e) {

    if (e.getKeyCode() == KeyEvent.VK_LEFT) {
        left = true;
        System.out.println("Left key pressed");

        }
    if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
        right = true;
        System.out.println("Left key pressed");
        }
}

public void keyReleased(KeyEvent e) {

    if (e.getKeyCode() == KeyEvent.VK_LEFT) {
        left = false;
        }
    if (e.getKeyCode() == KeyEvent.VK_RIGHT) {
        right = false;
        }
}
public void paint (Graphics g){
    d.clearRect(0, 0, 854, 480);
    d.drawOval(x, y, 20, 20);
    g.drawImage(offscreen, 0, 0, this);
}

public void update(Graphics g){
    paint(g);
}

}

谢谢！