即使条件为 false，Java do-while 循环也会继续

您遇到的问题

请注意，您有嵌套循环。

do{
    while(CardDealt <= numCards){
        //...
        response = scan.next().charAt(0);
    }
} while(response == 'Y'); 

因此，您只会循环直到所有牌都发完为止，然后才检查响应。

相反，您可以将检查集成到 -loop 中：CardDealt <= numCardsdo while

do{
    //...
    response = scan.next().charAt(0);
} while(response == 'Y' && CardDealt <= numCards); 

这将检查每次迭代中的响应，如果不是，则停止循环。Y

其他问题/改进

重新创造Scanner

另外，我不建议您在每次迭代中都创建一个新的。相反，您可以在整个程序中重复使用相同的扫描仪：Scanner

Scanner scan = new Scanner(System.in);//before the loop
do{
    //...
    //also do not create the scanner here
    response = scan.next().charAt(0);
} while(response == 'Y' && CardDealt <= numCards); 

一张牌抽得太多了

正如评论中所述，当已经发了 52 张牌时，您也抽了一张牌，这也太多了（这在一差错误中称为）。而不是 ，您需要使用（只有在取用少于 52 张卡时才取另一张卡）。CardDealt <= numCardsCardDealt < numCards

Scanner scan = new Scanner(System.in);//before the loop
do{
    //...
    //also do not create the scanner here
    response = scan.next().charAt(0);
} while(response == 'Y' && CardDealt < numCards); //< instead of <= here

重复取卡

饰演 Ole V.V. 在评论中提到，您的代码可能会多次选择同一张卡。

如果您能够使用收集 API（如果您不能使用数组，则不太可能），您可以通过收集列表中的所有卡片、对其进行随机播放，然后每次删除一张卡片来解决这个问题。

public record Card(String name, String suit){}//or similar

然后，您可以使用循环创建卡片列表：

List<String> cardNames=List.of("Ace", "2", "3", "4", "5", "6", "7", "8", "9", "10",  "Jack", "Queen", "King");
List<String> suitNames=List.of("Diamonds","Clubs","Hearts","Spades");
List<Card> cards=new ArrayList<>();

//go through all combinations of card and suit names
for(String cardName:cardNames){
    for(String suitName:suitNames){
        //add that as a card
        cards.add(new Card(cardName, suitName))
    }
}

//shuffle the list of cards
Collections.shuffle(cards);

//draw a card
//just do this every time you draw a card
int index=cards.size()-1;
Card card=cards.remove(index);

//check whether there are cards left
//!cards.isEmpty()

在代码中将它们放在一起：

List<String> cardNames=List.of("Ace", "2", "3", "4", "5", "6", "7", "8", "9", "10",  "Jack", "Queen", "King");
List<String> suitNames=List.of("Diamonds","Clubs","Hearts","Spades");
List<Card> cards=new ArrayList<>();

//go through all combinations of card and suit names
for(String cardName:cardNames){
    for(String suitName:suitNames){
        //add that as a card
        cards.add(new Card(cardName, suitName))
    }
}

//shuffle the list of cards
Collections.shuffle(cards);


char response = ' ';
Scanner scan = new Scanner(System.in);
do{
    int index=cards.size()-1;
    Card card=cards.remove(index);
    System.out.println("The card is" + " " + card.name() + " " + "of" + " " + card.suit());
    System.out.println("Do you want another card? (Enter Y or N)");
    response = scan.next().charAt(0);
} while(response == 'Y' && !cards.isEmpty()); 

在另一个文件中：

public record Card(String name, String suit){}