如何在HashMap中打印特定值的键？

Question

问题是如何使用printWhiterAvens(arrayList whiteRavens) 方法在HashMap中pritn值=1的图书？在代码中，ive删除了数组中的书籍，这样代码就可以更短。

 public static HashMap<String, Integer> createBooksCounter() {
        HashMap<String,Integer> createBooksCounter = new HashMap<>();
        createBooksCounter.put("Chicken Abroad",5);
        createBooksCounter.put("Lord With Sins",3);
        createBooksCounter.put("Fish And Horses",4);
        createBooksCounter.put("Mistress Of Devotion",2);
        createBooksCounter.put("Guardians And Gangsters",3);
        createBooksCounter.put("Bandit Of The Void",1);
        createBooksCounter.put("Lions Of Dread",1);
        createBooksCounter.put("Future Of Fire",2);
        createBooksCounter.put("Driving Into The Depths",1);
        createBooksCounter.put("Starting The Demons",1);
        createBooksCounter.put("Maid With Blue Eyes",2);
        createBooksCounter.put("Lovers In The Forest",1);
        createBooksCounter.put("Destruction Of The Faceless Ones",1);

        return null;
    }

    public static void countBook(HashMap<String, Integer> booksCounter, String book) {

    }

    public static ArrayList<String> findWhiteRavens(HashMap<String, Integer> booksCounter) {
        return null;    
    }

    public static void printWhiteRavens(ArrayList<String> whiteRavens) {
        return null;
    }

    public static void main(String[] args) {
    }

Answer 1

使用流：

yourMap.entrySet().stream().filter(e -> e.getValue() == 1)
                .forEach(element -> System.out.println(element.getKey()));