HashMap遍历

    HashMap< Integer, Integer> hashMap=new HashMap<>();hashMap.put(2, 3);hashMap.put(5,6);Iterator  iterator=hashMap.entrySet().iterator();while (iterator.hasNext()) {    HashMap.Entry entry =  (Entry) iterator.next();    int a=(int) entry.getKey();    int b=(int) entry.getValue();    System.out.println(a+"  "+b);}