JSD-2204-面向对象-潜艇游戏--Day08

已于 2022-05-11 18:19:21 修改
阅读量635 收藏
点赞数
CC 4.0 BY-SA版权
文章标签： java
于 2022-05-11 18:14:01 首次发布
版权声明：本文为博主原创文章，遵循 CC 4.0 BY-SA 版权协议，转载请附上原文出处链接和本声明。
本文链接：https://blog.youkuaiyun.com/TheNewSystrm/article/details/124715755
本文介绍了Java中的构造方法，用于初始化成员变量，并讲解了this关键字的作用，特别是在解决成员变量与局部变量同名时的使用。此外，还探讨了NULL的概念。文章以潜艇游戏为背景，详细讲述了如何为6个类添加构造方法并进行测试，包括Battleship, Bomb, Mine, MineSubMarine, ObserverSubMarine, TorpedoSubmarine以及测试类World。同时，补充了内存管理的基本概念，强调了JVM对堆和栈的管理。" 52266365,4831857,离线处理DAG：Codeforces Round #368 Div. 2 D题解析,"['算法', '图论', '数据结构', '编程竞赛', '回溯法']

摘要生成于 C知道 ，由 DeepSeek-R1 满血版支持， 前往体验 >

1.构造方法：

构造函数、构造器、构建器-----------复用给成员变量初始化代码

  • 作用：给成员变量赋初始值
  • 与类同名，没有返回值类型(连void都没有)
  • 在创建(new)对象时被自动调用
  • 若自己不写构造方法，则编译器默认提供一个无参构造方法，
  • 若自己写了构造方法，则不再默认提供
  • 构造方法可以重载

2.this

  • 指代当前对象，哪个对象调用方法它指的就是哪个对象
  • 只能用在方法中，方法中访问成员变量之前默认有个this.

2.1this的用法

  • this.成员变量名--------------访问成员变量
    • 当成员变量和局部变量同名时，若想访问成员变量则this不能省略，其它一般省略
  • this.方法名()------------------调用方法(一般不用，了解)
  • this()----------------------------调用构造方法(一般不用，了解)
   class Student {
       //成员变量
       String name;
       int age;
       String address;
       //构造方法
       Student(String name,int age,String address){
           this.name = name;       //zs.name="zhangsan"
           this.age = age;         //zs.age=25
           this.address = address; //zs.address="LF"
       }
   
       //方法
       void study(){
           System.out.println(name+"在学习...");
       }
       void sayHi(){
           System.out.println("大家好，我叫"+name+"，今年"+age+"岁了，家住"+address);
       }
   }
   
   //构造方法和this的演示
   public class ConsDemo {
       public static void main(String[] args) {
           //Student zs = new Student(); //编译错误，Student类没有无参构造
           Student zs = new Student("zhangsan",25,"LF");
           Student ls = new Student("lisi",26,"JMS");
           zs.sayHi();
           ls.sayHi();
       }
   }

3.NULL

表示空，没有指向任何对象。若引用的值为null，则该引用不能再进行任何点操作了，若操作则发生NullPointerException空指针异常。

4.潜艇游戏第二天

图解（潜艇y坐标）：

图解（坐标图）：

4.1给6个类添加构造方法，并测试

4.1.1Battleship类

package cn.tedu.submarine;

import java.util.Objects;

/**
 * 战舰
 */
public class Battleship {
    /**
     * 宽
     */
    private int width;
    /**
     * 高
     */
    private int height;
    /**
     * x轴
     */
    private int x;
    /**
     * y轴
     */
    private int y;
    /**
     * 命
     */
    private int life;
    /**
     * 移动的速度
     */
    private int speed;

    public Battleship() {
        this.width = 66;
        this.height = 26;

        this.x = 270;
        this.y = 124;

        this.life = 5;
        this.speed = 20;
    }

    public Battleship(int width, int height, int x, int y, int life, int speed) {
        this.width = width;
        this.height = height;
        this.x = x;
        this.y = y;
        this.life = life;
        this.speed = speed;
    }

    /**
     * 移动战舰的方法
     */
    public void move(){
        System.out.println("战舰移动");
    }

    /**
     * 发射炸弹的方法
     */
    public void shootBomb(){

    }





    @Override
    public String toString() {
        return "Battleship{" +
                "width=" + width +
                ", height=" + height +
                ", x=" + x +
                ", y=" + y +
                ", life=" + life +
                ", speed=" + speed +
                '}';
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Battleship that = (Battleship) o;
        return width == that.width &&
                height == that.height &&
                x == that.x &&
                y == that.y &&
                life == that.life &&
                speed == that.speed;
    }

    @Override
    public int hashCode() {
        return Objects.hash(width, height, x, y, life, speed);
    }

    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 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 getLife() {
        return life;
    }

    public void setLife(int life) {
        this.life = life;
    }

    public int getSpeed() {
        return speed;
    }

    public void setSpeed(int speed) {
        this.speed = speed;
    }
}

4.1.2Bomb类

package cn.tedu.submarine;

import java.util.Objects;

/**
 * 炸弹
 */
public class Bomb {
    /**
     * 宽
     */
    private int width;
    /**
     * 高
     */
    private int height;
    /**
     * x轴
     */
    private int x;
    /**
     * y轴
     */
    private int y;
    /**
     * 速度
     */
    private int speed;

    public Bomb(int x , int y) {
        this.width = 9;
        this.height = 12;
        this.x = x;
        this.y = y;
        this.speed = 3;
    }

    public Bomb(int width, int height, int x, int y, int speed) {
        this.width = width;
        this.height = height;
        this.x = x;
        this.y = y;
        this.speed = speed;
    }

    /**
     * 炸弹移动的方法
     */
    public void move(){
        System.out.println("炸弹移动");
    }



    @Override
    public String toString() {
        return "Bomb{" +
                "width=" + width +
                ", height=" + height +
                ", x=" + x +
                ", y=" + y +
                ", speed=" + speed +
                '}';
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Bomb bomb = (Bomb) o;
        return width == bomb.width &&
                height == bomb.height &&
                x == bomb.x &&
                y == bomb.y &&
                speed == bomb.speed;
    }

    @Override
    public int hashCode() {
        return Objects.hash(width, height, x, y, speed);
    }

    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 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 getSpeed() {
        return speed;
    }

    public void setSpeed(int speed) {
        this.speed = speed;
    }
}

4.1.3Mine类

package cn.tedu.submarine;

import java.util.Objects;

/**
 * 水雷
 */
public class Mine {
    /**
     * 宽
     */
    private int width;
    /**
     * 高
     */
    private int height;
    /**
     * x轴
     */
    private int x;
    /**
     * y轴
     */
    private int y;
    /**
     * 速度
     */
    private int speed;

    public Mine(int x , int y) {
        this.width = 11;
        this.height = 11;
        this.x = x;
        this.y = y;
        this.speed = 1;
    }

    public Mine(int width, int height, int x, int y, int speed) {
        this.width = width;
        this.height = height;
        this.x = x;
        this.y = y;
        this.speed = speed;
    }

    /**
     * 水雷移动的方法
     */
    public void move(){
        System.out.println("水雷移动");
    }





    @Override
    public String toString() {
        return "Mine{" +
                "width=" + width +
                ", height=" + height +
                ", x=" + x +
                ", y=" + y +
                ", speed=" + speed +
                '}';
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Mine mine = (Mine) o;
        return width == mine.width &&
                height == mine.height &&
                x == mine.x &&
                y == mine.y &&
                speed == mine.speed;
    }

    @Override
    public int hashCode() {
        return Objects.hash(width, height, x, y, speed);
    }

    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 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 getSpeed() {
        return speed;
    }

    public void setSpeed(int speed) {
        this.speed = speed;
    }
}

4.1.4MineSubMarine类

package cn.tedu.submarine;

import java.util.Objects;
import java.util.Random;

/**
 * 水雷潜艇
 */
public class MineSubmarine {
    /**
     * 宽
     */
    private int width;
    /**
     * 高
     */
    private int height;
    /**
     * x轴
     */
    private int x;
    /**
     * y轴
     */
    private int y;
    /**
     * 速度
     */
    private int speed;

    public MineSubmarine() {
        this.width = 63;
        this.height = 19;
        Random rand = new Random();
        x = -width;
        y = rand.nextInt(479-height-150+1 ) +150;
        this.speed = rand.nextInt(3)+1;
    }

    public MineSubmarine(int width, int height, int x, int y, int speed) {
        this.width = width;
        this.height = height;
        this.x = x;
        this.y = y;
        this.speed = speed;
    }


    /**
     * 水雷潜艇移动的方法
     */
    public void move(){
        System.out.println("水雷潜艇移动");
    }




    @Override
    public String toString() {
        return "MineSubmarine{" +
                "width=" + width +
                ", height=" + height +
                ", x=" + x +
                ", y=" + y +
                ", speed=" + speed +
                '}';
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        MineSubmarine that = (MineSubmarine) o;
        return width == that.width &&
                height == that.height &&
                x == that.x &&
                y == that.y &&
                speed == that.speed;
    }

    @Override
    public int hashCode() {
        return Objects.hash(width, height, x, y, speed);
    }

    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 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 getSpeed() {
        return speed;
    }

    public void setSpeed(int speed) {
        this.speed = speed;
    }
}

4.1.5ObserverSubMarine类

package cn.tedu.submarine;

import java.util.Objects;
import java.util.Random;

/**
 * 侦察潜艇
 */
public class ObserverSubmarine {
    /**
     * 宽
     */
    private int width;
    /**
     * 高
     */
    private int height;
    /**
     * x轴
     */
    private int x;
    /**
     * y轴
     */
    private int y;
    /**
     * 速度
     */
    private int speed;

    public ObserverSubmarine() {
        this.width = 63;
        this.height = 19;
        Random rand = new Random();
        x = -width;
        y = rand.nextInt(479-height-150+1 ) +150;
        this.speed = rand.nextInt(3)+1;
    }

    public ObserverSubmarine(int width, int height, int x, int y, int speed) {
        this.width = width;
        this.height = height;
        this.x = x;
        this.y = y;
        this.speed = speed;
    }

    /**
     * 侦察潜艇移动的方法
     */
    public void move(){
        System.out.println("侦察潜艇移动");
    }


    @Override
    public String toString() {
        return "ObserverSubmarine{" +
                "width=" + width +
                ", height=" + height +
                ", x=" + x +
                ", y=" + y +
                ", speed=" + speed +
                '}';
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        ObserverSubmarine that = (ObserverSubmarine) o;
        return width == that.width &&
                height == that.height &&
                x == that.x &&
                y == that.y &&
                speed == that.speed;
    }

    @Override
    public int hashCode() {
        return Objects.hash(width, height, x, y, speed);
    }

    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 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 getSpeed() {
        return speed;
    }

    public void setSpeed(int speed) {
        this.speed = speed;
    }
}

4.1.6TorpedoSubmarine类

package cn.tedu.submarine;

import java.util.Objects;
import java.util.Random;

/**
 * 鱼类潜艇
 */
public class TorpedoSubmarine {
    /**
     * 宽
     */
    private int width;
    /**
     * 高
     */
    private int height;
    /**
     * x轴
     */
    private int x;
    /**
     * y轴
     */
    private int y;
    /**
     * 速度
     */
    private int speed;

    public TorpedoSubmarine() {
        this.width = 64;
        this.height = 20;
        Random rand = new Random();
        x = -width;
        y = rand.nextInt(479-height-150+1 ) +150;
        this.speed = rand.nextInt(3)+1;
    }

    public TorpedoSubmarine(int width, int height, int x, int y, int speed) {
        this.width = width;
        this.height = height;
        this.x = x;
        this.y = y;
        this.speed = speed;
    }

    /**
     * 鱼类潜艇移动的方法
     */
    public void move(){
        System.out.println("鱼类潜艇移动");
    }


    @Override
    public String toString() {
        return "TorpedoSubmarine{" +
                "width=" + width +
                ", height=" + height +
                ", x=" + x +
                ", y=" + y +
                ", speed=" + speed +
                '}';
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        TorpedoSubmarine that = (TorpedoSubmarine) o;
        return width == that.width &&
                height == that.height &&
                x == that.x &&
                y == that.y &&
                speed == that.speed;
    }

    @Override
    public int hashCode() {
        return Objects.hash(width, height, x, y, speed);
    }

    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 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 getSpeed() {
        return speed;
    }

    public void setSpeed(int speed) {
        this.speed = speed;
    }
}

4.1.7World（测试类）

package cn.tedu.submarine;

/**
 * 整个游戏世界
 */
public class World {
    public static void main(String[] args) {
        Battleship s = new Battleship();
        ObserverSubmarine os1 = new ObserverSubmarine();
        ObserverSubmarine os2 = new ObserverSubmarine();
        ObserverSubmarine os3 = new ObserverSubmarine();
        ObserverSubmarine os4 = new ObserverSubmarine();
        TorpedoSubmarine ts1 = new TorpedoSubmarine();
        TorpedoSubmarine ts2 = new TorpedoSubmarine();
        MineSubmarine ms1 = new MineSubmarine();
        MineSubmarine ms2 = new MineSubmarine();
        Mine m1 = new Mine(ms1.getX(),ms1.getY());
        Mine m2 = new Mine(ms2.getX(),ms2.getY());
        Bomb b1 = new Bomb(s.getX(),s.getY());
        Bomb b2 = new Bomb(s.getX(),s.getY());
        System.out.println(s.toString());
        System.out.println(os1.toString());
        System.out.println(os2.toString());
        System.out.println(os3.toString());
        System.out.println(os4.toString());
        System.out.println(ts1.toString());
        System.out.println(ts2.toString());
        System.out.println(ms1.toString());
        System.out.println(ms2.toString());
        System.out.println(m1.toString());
        System.out.println(m2.toString());
        System.out.println(b1.toString());
        System.out.println(b2.toString());
    }
}

5.补充

成员变量和局部变量是可以同名的，但是使用的时候默认采取的是就近原则

5.1内存管理：由JVM管理

  • 堆：new出来的对象(包括成员变量)
  • 栈：局部变量(包括方法的参数)
  • 方法区：------------周五再讨论

图解：

基本类型变量中装的是具体的数，引用类型变量中装的是堆中对象的地址

 5.2明日单词

   1)reference:引用
   2)extends:继承
   3)super:超级
   4)Sea:海洋
   5)object:对象

评论
添加红包

请填写红包祝福语或标题

个

红包个数最小为10个

元

红包金额最低5元

当前余额3.43元 前往充值 >
需支付：10.00元
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付元
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明：

1.余额是钱包充值的虚拟货币，按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载，可以购买VIP、付费专栏及课程。

余额充值