hashMap - hashCode & equals 方法返回类型

问题描述

我正在 Java 上开发纸牌游戏，我正在尝试将 hashMap 中的键与 ArrayList 中的元素进行比较（两者都是对象）。 hashCode() 和 equals() 被覆盖，但出现了一个错误，我不确定它的哪一部分是错误的。

这是卡片类

class Cards implements Comparable<Cards> {
    public String suit;
    public String face;
    
    public Cards() {
        
    }

    //Create Cards object 
    public Cards (String suit,String face){
        this.suit = suit;
        this.face = face;
    }

    //Return card suit
    public String getSuit() {
        return suit;
    }

    //Return card face
    public String getFace() {
        return face;
    }
    
    
    @Override
    public int compareto(Cards currentCards) {
        if (getSuit().compareto(currentCards.getSuit()) > 0) {
            return 1; 
        } else if ((getSuit().compareto(currentCards.getSuit())) < 0){
            return -1; 
        } else if ((getSuit().compareto(currentCards.getSuit())) == 0){
            if (getFace().compareto(currentCards.getFace()) > 0){
                return 1;
            } else if (getFace().compareto(currentCards.getFace()) < 0){
                return -1;
            }
        }
        return 0;
            
    }
    
    @Override
    public boolean equals(Object o) {
        if (o == this)
            return true;
        if (!(o instanceof Cards))
            return false;
        Cards other = (Cards)o;
        boolean suitEquals = (this.suit == null && other.suit == null) ||
                        (this.suit != null && this.suit.equals(other.suit));
        boolean faceEquals = (this.face == null && other.face == null) ||
                        (this.face != null && this.face.equals(other.face));
        return suit && face;
            
    }
    
    @Override
    public int hashCode() {
        int result = 17;
        if (suit != null) {
            result = 31 * result + suit.hashCode();
        }
        if (face != null) {
            result = 31 * result + face.hashCode();
        }
        return result;
    }

}

以及我们正在尝试进行的比较

/**Creating Cards object*/
String[] SUIT = new String[]{ "d","c","h","s" };
String[] FACE = new String[]{ null,"A","2","3","4","5","6","7","8","9","X","J","Q","K" };
Cards[] cardDeck = new Cards[52];
int index = 0;
    
  for (int i = 0; i <= 3; i++) {
      for (int j = 1; j <= 13; j++) {
          cardDeck[index] = new Cards(SUIT[i],FACE[j]);
          index++;
      }
  }

/**Player 1 in hand*/
ArrayList<Cards> player1 = new ArrayList<Cards>();
int j=0;

for (int i = 0; i <18; i++){
        player1.add(i,cardDeck[j++]);
    }

for(Cards n : player1){
    if (Points.containsKey(n)){
        System.out.println("Card points: " + Points.get(n)); 
    }
}

错误： click to see picture of error

解决方法

您正在尝试使用两个 String 对象作为布尔对象：

换回西装&&脸；在你的equals方法中返回suitEquals && faceEquals。