GitHub地址：https://github.com/WingedCat/AirWar

子弹类的创建：

package cn.xpu.hcp.entity;

import java.awt.Graphics;
import java.awt.Image;
import java.util.Random;

import cn.xpu.hcp.game.GameFrame;
import cn.xpu.hcp.tools.Constant;
import cn.xpu.hcp.tools.GameImage;

public class Bullet {
    private static Random r = new Random(); 
    int randIndex;
    private int x,y;//子弹的位置
    int WIDTH,HEIGHT;//子弹的宽和高

    public void setX(int x) {
        this.x = x;
    }

    public void setY(int y) {
        this.y = y;
    }

    private boolean good;//子弹是我还是对方（敌机）发射的；我设置为true，敌机设置为false
    private boolean isAlive = true;//表明子弹是否应该消失，击中活着出界就设置为false
    private int power;//子弹的杀伤力
    private int speed;//子弹的移动速度
    private boolean isBoss;//是否为boss机型子弹
    private Direction dir;//子弹的方向，我是向上，敌方向下
    private GameFrame gf;

    private static Image[] myImgs=new Image[13];//存放我方子弹图片的数组
    private static Image[] enemyImgs = new Image[8];//存放敌方普通机型子弹的图片
    private static Image[] bossImgs = new Image[5];//存放敌方boss机型子弹的图片
    private Image ensureImg;//具体确定的图片

    static{
        //我方飞机子弹图片
        //低级子弹
        myImgs[0]=GameImage.getImage("resources/m5.png");  
        myImgs[1]= GameImage.getImage("resources/m6.png");  
        myImgs[2]= GameImage.getImage("resources/m7.png");  
        //中级子弹
        myImgs[3]= GameImage.getImage("resources/m1.png"); 
        //高级子弹
        myImgs[4]= GameImage.getImage("resources/m2.png");  
        myImgs[5]= GameImage.getImage("resources/m3.png");  
        myImgs[6]= GameImage.getImage("resources/m4.png"); 
        myImgs[7]= GameImage.getImage("resources/m8.png");
        myImgs[8]= GameImage.getImage("resources/m9.png");
        //超级炮弹
        myImgs[9]= GameImage.getImage("resources/m10.png");  
        myImgs[10]= GameImage.getImage("resources/m11.png"); 
        myImgs[11]= GameImage.getImage("resources/m12.png");
        myImgs[12]= GameImage.getImage("resources/m13.png");

        //敌方普通飞机子弹图片
        enemyImgs[0]=GameImage.getImage("resources/em1.png");  
        enemyImgs[1]= GameImage.getImage("resources/em2.png");  
        enemyImgs[2]= GameImage.getImage("resources/em3.png");  
        enemyImgs[3]= GameImage.getImage("resources/em4.png");  
        enemyImgs[4]= GameImage.getImage("resources/em5.png");  
        enemyImgs[5]= GameImage.getImage("resources/em6.png");  
        enemyImgs[6]= GameImage.getImage("resources/em7.png");  
        enemyImgs[7]= GameImage.getImage("resources/em8.png"); 

        //boss子弹图片
        //低级子弹
        bossImgs[0]=GameImage.getImage("resources/bm3.png");  
        bossImgs[1]= GameImage.getImage("resources/bm5.png");
        //高级子弹
        bossImgs[2]= GameImage.getImage("resources/bm4.png");
        //大招
        bossImgs[3]= GameImage.getImage("resources/bm1.png");  
        bossImgs[4]= GameImage.getImage("resources/bm2.png"); 
    }

    public int getWIDTH() {
        return WIDTH;
    }

    public int getHEIGHT() {
        return HEIGHT;
    }

    public Bullet(int x,int y,int speed,int randIndex,boolean good,GameFrame gf){
        this.x = x;
        this.y = y;
        this.speed = speed;
        this.good = good;
        this.gf = gf;
        this.randIndex = randIndex;
        if(good==true){
            //开始只能是低级子弹，通过拾取宝贝升级子弹
            ensureImg = myImgs[randIndex];
            dir = Direction.U;
            WIDTH = ensureImg.getWidth(null);
            HEIGHT = ensureImg.getHeight(null);
        }else{
            dir = Direction.D;
            if(isBoss){
                //开始发射低级子弹，随机发射高级和大招
                ensureImg = bossImgs[randIndex];
                WIDTH = ensureImg.getWidth(null);
                HEIGHT = ensureImg.getHeight(null);

            }else{
                ensureImg = enemyImgs[randIndex];
                WIDTH = ensureImg.getWidth(null);
                HEIGHT = ensureImg.getHeight(null);
            }
        }

    }

    public void draw(Graphics g){
        if(!isAlive){
            gf.bs.remove(this);//销毁子弹
            return;//子弹消失了，不画
        }
        g.drawImage(ensureImg,x,y,null);
        move();
    }

    private void move() {  
        switch(dir) {  
        case U:  
            y -= speed;  
            break; 
        case D:
            y += speed;  
            break;  
        }  
        if(x < 0 || y < 0 || x > Constant.GAME_WIDTH || y > Constant.GAME_HEIGHT) {  
            isAlive = false;//出界就设置为false  
        }
    }
}

飞机子弹的发射：
fire()方法：

public void fire() {
        if(isAlive==false)return;//不存活，也就没开火的必要了
        new PlaySound("Beam.mp3", false).start();
        int xPos = -10;  
        int yPos = -10;  
        Bullet m = new Bullet(xPos, yPos,10,randIndex, good,this.gf); 
        m.setX(this.x + Plane.WIDTH/2 - m.getWIDTH()/2);
        m.setY(this.y   - m.getHEIGHT()+20);
        gf.bs.add(m);//集合中添加子弹  

    }
    public void fire(long t){//鼠标调用此方法
        if(r.nextInt(40)>36)//不要每一次都开火
            fire();
    }

private class MouseMonitor extends MouseAdapter{
        @Override
        public void mousePressed(MouseEvent e) {

        }

        @Override
        public void mouseReleased(MouseEvent e) {
            if(e.getModifiers()==16)//左键释放就开火
             myplane.fire();
        }

        @Override
        public void mouseMoved(MouseEvent e) {
            if(useMouse){
                myplane.setX(e.getX());
                myplane.setY(e.getY());
            }
        }

        @Override
        public void mouseDragged(MouseEvent e) {
            if(useMouse){
                if(e.getModifiers()==16){
                    myplane.fire(0);//开火
                }
                myplane.setX(e.getX());
                myplane.setY(e.getY());
            }
        }

子弹的绘制：

//绘制子弹
        for(int i=0; i<bs.size(); i++) {//将集合中的子弹都绘制出来  
            Bullet b = bs.get(i);  
            b.draw(g);  
        } 

子弹销毁：

 if(x < 0 || y < 0 || x > Constant.GAME_WIDTH || y > Constant.GAME_HEIGHT) {  
            isAlive = false;//出界就设置为false  
        }

public void draw(Graphics g){
        if(!isAlive){
            gf.bs.remove(this);//销毁子弹
            return;//子弹消失了，不画
        }
        g.drawImage(ensureImg,x,y,null);
        move();
    }