[JAVA] HashMap Key To Array (HashMap KeySet To Array)

String[] array = hashMap.keySet().toArray(new String[hashMap.size()]);

    public static void main(String[] args) {
        HashMap<String, Integer> hashMap = new HashMap<String, Integer>();
        hashMap.put(“a”, 1);
        hashMap.put(“b”, 2);
        hashMap.put(“c”, 3);
        hashMap.put(“d”, 4);
       
        hashMap.put(“키1”, 5);
        hashMap.put(“키2”, 6);
        hashMap.put(“키3”, 7);
       
        hashMap.put(“키3”, 10);
        hashMap.put(“키3”, 20);
       
        String[] array = hashMap.keySet().toArray(new String[hashMap.size()]);
       
        int len = array.length;

        System.out.println(“len : ” + len);

        System.out.println();
        for (int i=0; i<len; i++) {
            System.out.println(i + ” : “+ array[i]);
        }
    }

len : 7

0 : a
1 : b
2 : c
3 : d
4 : 키1
5 : 키3
6 : 키2