Java Shooting Game Example Demonstrating OOP Concepts

The author shares a full Java desktop shooting‑game project to help readers understand object‑oriented programming (OOP) through practical code examples.

Airplane (enemy plane) class:

import java.util.Random;

public class Airplane extends FlyingObject implements Enemy {
    private int speed = 3;  //移动步骤

    /** 初始化数据 */
    public Airplane(){
        this.image = ShootGame.airplane;
        width = image.getWidth();
        height = image.getHeight();
        y = -height;            
        Random rand = new Random();
        x = rand.nextInt(ShootGame.WIDTH - width);
    }

    @Override
    public int getScore() {   
        return 5;
    }

    @Override
    public boolean outOfBounds() {   
        return y>ShootGame.HEIGHT;
    }

    @Override
    public void step() {   
        y += speed;
    }
}

Award interface (score rewards):

/** 
 * 奖励 
 */  
public interface Award {  
    int DOUBLE_FIRE = 0;  //双倍火力  
    int LIFE = 1;   //1条命  
    /** 获得奖励类型(上面的0或1) */  
    int getType();  
}

Bee (reward object) class:

import java.util.Random;  

/** 蜜蜂 */  
public class Bee extends FlyingObject implements Award{  
    private int xSpeed = 1;   //x坐标移动速度   
    private int ySpeed = 2;   //y坐标移动速度   
    private int awardType;    //奖励类型   

    /** 初始化数据 */   
    public Bee(){   
        this.image = ShootGame.bee;   
        width = image.getWidth();   
        height = image.getHeight();   
        y = -height;   
        Random rand = new Random();   
        x = rand.nextInt(ShootGame.WIDTH - width);   
        awardType = rand.nextInt(2);   //初始化时给奖励   
    }   

    public int getType(){   
        return awardType;   
    }   

    @Override   
    public boolean outOfBounds() {   
        return y>ShootGame.HEIGHT;   
    }   

    @Override   
    public void step() {        
        x += xSpeed;   
        y += ySpeed;   
        if(x > ShootGame.WIDTH-width){    
            xSpeed = -1;   
        }   
        if(x < 0){   
            xSpeed = 1;   
        }   
    }   
}

Bullet class (projectile):

/** 
 * 子弹类:是飞行物 
 */  
public class Bullet extends FlyingObject {  
    private int speed = 3;  //移动的速度   

    /** 初始化数据 */   
    public Bullet(int x,int y){   
        this.x = x;   
        this.y = y;   
        this.image = ShootGame.bullet;   
    }   

    @Override   
    public void step(){      
        y-=speed;   
    }   

    @Override   
    public boolean outOfBounds() {   
        return y<-height;   
    }   
}

Enemy interface (scorable enemies):

/** 
 * 敌人，可以有分数 
 */  
public interface Enemy {  
    /** 敌人的分数  */  
    int getScore();  
}

FlyingObject abstract base class (common properties and collision logic):

import java.awt.image.BufferedImage;  

/** 
 * 飞行物(敌机，蜜蜂，子弹，英雄机) 
 */  
public abstract class FlyingObject {  
    protected int x;    //x坐标 
    protected int y;    //y坐标 
    protected int width;    //宽 
    protected int height;    //高 
    protected BufferedImage image;    //图片 

    public int getX() { return x; }
    public void setX(int x) { this.x = x; }
    public int getY() { return y; }
    public void setY(int y) { this.y = y; }
    public int getWidth() { return width; }
    public void setWidth(int width) { this.width = width; }
    public int getHeight() { return height; }
    public void setHeight(int height) { this.height = height; }
    public BufferedImage getImage() { return image; }
    public void setImage(BufferedImage image) { this.image = image; }

    public abstract boolean outOfBounds();
    public abstract void step();

    public boolean shootBy(Bullet bullet){   
        int x = bullet.x;  //子弹横坐标   
        int y = bullet.y;  //子弹纵坐标   
        return this.x<x && x<this.x+width && this.y<y && y<this.y+height;   
    }
}

Hero class (player’s aircraft with double fire and life management):

import java.awt.image.BufferedImage;  

/** 
 * 英雄机:是飞行物
 */  
public class Hero extends FlyingObject{  
    private BufferedImage[] images = {};  //英雄机图片   
    private int index = 0;                 //英雄机图片切换索引   
    private int doubleFire;   //双倍火力   
    private int life;   //命   

    public Hero(){   
        life = 3;   //初始3条命   
        doubleFire = 0;   //初始火力为0   
        images = new BufferedImage[]{ShootGame.hero0, ShootGame.hero1}; //英雄机图片数组   
        image = ShootGame.hero0;   //初始为hero0图片   
        width = image.getWidth();   
        height = image.getHeight();   
        x = 150;   
        y = 400;   
    }
    // getters/setters for doubleFire and life omitted for brevity
    @Override
    public boolean outOfBounds() { return false; }
    public Bullet[] shoot(){ 
        int xStep = width/4; 
        int yStep = 20; 
        if(doubleFire>0){ 
            Bullet[] bullets = new Bullet[2];
            bullets[0] = new Bullet(x+xStep,y-yStep);
            bullets[1] = new Bullet(x+3*xStep,y-yStep);
            return bullets;
        }else{ 
            Bullet[] bullets = new Bullet[1];
            bullets[0] = new Bullet(x+2*xStep,y-yStep);
            return bullets;
        }
    }
    @Override
    public void step() { 
        if(images.length>0){ 
            image = images[index++/10%images.length];
        }
    }
    public boolean hit(FlyingObject other){ 
        int x1 = other.x - this.width/2; 
        int x2 = other.x + this.width/2 + other.width; 
        int y1 = other.y - this.height/2; 
        int y2 = other.y + this.height/2 + other.height; 
        int herox = this.x + this.width/2; 
        int heroy = this.y + this.height/2; 
        return herox>x1 && herox<x2 && heroy>y1 && heroy<y2; 
    }
}

Main game class (Swing panel handling rendering, input, timer, and game logic):

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import javax.swing.*;

public class ShootGame extends JPanel {
    public static final int WIDTH = 400; // 面板宽
    public static final int HEIGHT = 654; // 面板高
    private int state;
    private static final int START = 0, RUNNING = 1, PAUSE = 2, GAME_OVER = 3;
    private int score = 0;
    private Timer timer;
    private int intervel = 1000 / 100;
    public static BufferedImage background, start, airplane, bee, bullet, hero0, hero1, pause, gameover;
    private FlyingObject[] flyings = {};
    private Bullet[] bullets = {};
    private Hero hero = new Hero();
    static { /* load images */ }
    @Override public void paint(Graphics g) { /* draw background, hero, bullets, objects, score, state */ }
    // ... many helper methods: paintHero, paintBullets, paintFlyingObjects, paintScore, paintState
    public static void main(String[] args){ JFrame frame = new JFrame("Fly"); ShootGame game = new ShootGame(); frame.add(game); frame.setSize(WIDTH, HEIGHT); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setVisible(true); game.action(); }
    public void action(){ /* mouse listeners, timer task that calls enterAction, stepAction, shootAction, bangAction, outOfBoundsAction, checkGameOverAction, repaint */ }
    // ... implementations of enterAction, stepAction, shootAction, bangAction, outOfBoundsAction, checkGameOverAction, isGameOver, bang, nextOne
}

In the concluding section the author notes that image resources are omitted from the post and invites readers to request them, while also providing a mind‑map to further illustrate OOP concepts used in the game.