我对java有点陌生。我想写一个简单的游戏，它有一个玩家和敌人，当你按一些键如“空格”时，玩家大多数会朝正确的方向射击，但我不知道如何在游戏中渲染子弹。事实上，它不会在游戏中出现，也不会移动。
射击系统

package com.company;
import javax.swing.*;
import java.awt.*;
public class Bullet {
    GamePanel panel;//Game panel
    Rectangle hitBox;//Bullet
    public int x,y,width,height;
    boolean Shoot;
    public Bullet(int x , int y ,GamePanel panel)
    {
        this.panel = panel;
        this.x=x;
        this.y=y;
        height=15;
        width=15;
        hitBox = new Rectangle(x,y,width,height);
    }
    public void set()
    {
        if(Shoot) // where I have problem which Bullet doesn't move or doesn't appear
            move();
    }
    public void move()
    {
        x=x+10;
    }
    public void draw(Graphics2D gtd)
    {
        gtd.setColor(Color.RED);
        gtd.fillRect(x,y,width,height);
    }
}

设置游戏对象的游戏面板

package com.company;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.util.ArrayList;
import java.util.Timer;
import java.util.TimerTask;
public class GamePanel extends JPanel implements ActionListener {
    Player player;
    Timer gameTimer;
    Bullet bullet;
    public GamePanel(){
        player = new Player(400,300,this);
        bullet = new Bullet(player.x, player.y, this);
        gameTimer = new Timer();
        gameTimer.schedule(new TimerTask() {
            @Override
            public void run() {
                player.set();
        bullet.move();
                repaint();
            }
        },100,15);
    }
    public void paint(Graphics g){
        super.paint(g);
        Graphics2D gtd = (Graphics2D) g;
        player.draw(gtd);
        bullet.draw(gtd);
    }
    void keyPressed(KeyEvent e)
    {
        if(e.getKeyChar()=='w')
            player.keyUp=true;
        if(e.getKeyChar()=='a')
            player.keyLeft=true;
        if(e.getKeyChar()=='s')
            player.keyDown=true;
        if(e.getKeyChar()=='d')
            player.keyRight=true;
        if(e.getKeyChar()=='t')
            bullet.Shoot=true;
    }
    void keyReleased(KeyEvent e)
    {
        if(e.getKeyChar()=='w')
            player.keyUp=false;
        if(e.getKeyChar()=='a')
            player.keyLeft=false;
        if(e.getKeyChar()=='s')
            player.keyDown=false;
        if(e.getKeyChar()=='d')
            player.keyRight=false;
        if(e.getKeyChar()=='t')
            bullet.Shoot=false;
    }
    @Override
    public void actionPerformed(ActionEvent e) {
    }
}