创建和使用Card类和Deck类

/**
 * 时代Java公众号 - N o w J a  v a . c o m 提 供 
**/

import java.util.*;


public class DisplayDeck {

    public static void main(String[] args) {

        Deck deck = new Deck();

        for (int suit = Card.DIAMONDS; suit <= Card.SPADES; suit++) {

            for (int rank = Card.ACE; rank <= Card.KING; rank++) {

                Card card = deck.getCard(suit, rank);

                System.out.format("%s of %s%n",

                        card.rankToString(card.getRank()),

                        card.suitToString(card.getSuit()));

            }

        }

    }/**nowjava.com - 时代Java**/

}

class Deck {


    public static int numSuits = 4;

    public static int numRanks = 13;

    public static int numCards = numSuits * numRanks;


    private Card[][] cards;


    public Deck() {

        cards = new Card[numSuits][numRanks];

        for (int suit = Card.DIAMONDS; suit <= Card.SPADES; suit++) {

            for (int rank = Card.ACE; rank <= Card.KING; rank++) {

                cards[suit - 1][rank - 1] = new Card(rank, suit);

            }

        }

    }


    public Card getCard(int suit, int rank) {

        return cards[suit - 1][rank - 1];

    }

}

class Card {

    private final int rank;

    private final int suit;


    // Kinds of suits

    public final static int DIAMONDS = 1;

    public final static int CLUBS = 2;

    public final static int HEARTS = 3;

    public final static int SPADES = 4;


    // Kinds of ranks

    public final static int ACE = 1;

    public final static int DEUCE = 2;

    public final static int THREE = 3;

    public final static int FOUR = 4;

    public final static int FIVE = 5;

    public final static int SIX = 6;

    public final static int SEVEN = 7;

    public final static int EIGHT = 8;

    public final static int NINE = 9;

    public final static int TEN = 10;

    public final static int JACK = 11;

    public final static int QUEEN = 12;

    public final static int KING = 13;


    public Card(int rank, int suit) {

        assert isValidRank(rank);

        assert isValidSuit(suit);

        this.rank = rank;

        this.suit = suit;

    }


    public int getSuit() {

        return suit;

    }


    public int getRank() {

        return rank;

    }


    public static boolean isValidRank(int rank) {

        return ACE <= rank && rank <= KING;

    }


    public static boolean isValidSuit(int suit) {

        return DIAMONDS <= suit && suit <= SPADES;

    }


    public static String rankToString(int rank) {

        switch (rank) {

        case ACE:

            return "Ace";

        case DEUCE:

            return "Deuce";

        case THREE:

            return "Three";

        case FOUR:

            return "Four";

        case FIVE:

            return "Five";

        case SIX:

            return "Six";

        case SEVEN:

            return "Seven";

        case EIGHT:

            return "Eight";

        case NINE:

            return "Nine";

        case TEN:

            return "Ten";

        case JACK:

            return "Jack";

        case QUEEN:

            return "Queen";

        case KING:

            return "King";

        default:

            //Handle an illegal argument.  There are generally two

            //ways to handle invalid arguments, throwing an exception

            //(see the section on Handling Exceptions) or return null

            return null;

        }

    }


    public static String suitToString(int suit) {

        switch (suit) {

        case DIAMONDS:

            return "Diamonds";

        case CLUBS:

            return "Clubs";

        case HEARTS:

            return "Hearts";

        case SPADES:

            return "Spades";

        default:

            return null;

        }

    }


    public static void main(String[] args) {


        // must run program with -ea flag (java -ea ..) to

        // use assert statements

        assert rankToString(ACE) == "Ace";

        assert rankToString(DEUCE) == "Deuce";

        assert rankToString(THREE) == "Three";

        assert rankToString(FOUR) == "Four";

        assert rankToString(FIVE) == "Five";

        assert rankToString(SIX) == "Six";

        assert rankToString(SEVEN) == "Seven";

        assert rankToString(EIGHT) == "Eight";

        assert rankToString(NINE) == "Nine";

        assert rankToString(TEN) == "Ten";

        assert rankToString(JACK) == "Jack";

        assert rankToString(QUEEN) == "Queen";

        assert rankToString(KING) == "King";


        assert suitToString(DIAMONDS) == "Diamonds";

        assert suitToString(C