1.分析功能、抽取类：PokerManager和Poker

2.开始实现功能

 1).Poker类，管理一张牌的信息（点数 花色）

 2).PokerManager类，管理一副牌的所有操作（生成 洗牌 显示）

MyClass.java

public class MyClass {
    public static void main(String[] args){
        //创建管理器
        PokerManager manager = new PokerManager();
        //生成一副牌
        manager.generateOnePackOfCards();
        //洗牌
        manager.shuffle();
        //显示
        manager.show();
    }
}

Poker.java

public class Poker {
    private public String dot;//记录点数
    private public String pic;//记录花色


    //提供构造方法
    public Poker (String dot, String pic) {
        this.dot = dot;
        this.pic = pic;
    }

    //set和get方法
    public String getDot() {
        return dot;
    }

    public void setDot(String dot) {
        this.dot = dot;
    }

    public String getPic() {
        return pic;
    }

    public void setPic(String pic) {
        this.pic = pic;
    }
    
    //重写toString方法
    public String toString() {
        return dot+pic;
    }
}

PokerManager.java

public class PokerManager {
    //保存一副牌
    private ArrayList<Poker> pokers;

    //实现构造方法
    public PokerManager(){
        //初始化数组
        pokers = new ArrayList<>();
    }

    //生成一副牌
    public void generateOnePackOfCards(){
        for (int i = 0; i < Constants.POKER_DOTS.length; I++){
            //取出i对应的点数
            String dot = Constants.POKER_DOTS[i];
            //为这个点数创建4种花色
            for (int j = 0; j < Constants.POKER_PICS.length; j++){
                //取出j对应的花色
                String pic = Constants.POKER_PICS[j];
                //创建一张牌
                Poker poker = new Poker(dot, pic);
                //保存这张牌
                int index = i*4+j;
                pokers.add(poker);
            }
        }
    }

    //显示一副牌
    public void show(){
        int index = 0;
        for (Poker poker : pokers){
            System.out.println(poker);
            if ((index+1) % 8 == 0){
                System.out.println("");
            }
            index++;
        }
    }

    //洗牌
    public void shuffle(){
        Collections.shuffle(pokers);
    }
}

Constants.java

//final 修饰成员变量 表示这是一个常量 不能被更改
//      通常使用大写字母

public class Constants {
    //准备一个数组保存所有的点数
    public static final String[] POKER_DOTS = new String[]{"2","3","4","5","6","7","8","9","10","J","Q","K","A"};

    //花色
    public static final String[] POKER_PICS = new String[]{"♥","♣","♠","♦"};
}