HashMap的遍历

HashMap<String,Integer> hashMap=new HashMap<>();
        hashMap.put("hello",1);
        hashMap.put("hi",2);
        for(String a:hashMap.keySet())
        {
            System.out.println(a);//键
        }
        for(Integer integer:hashMap.values())
        {
            System.out.println(integer);//值
        }

HashMap<String,Integer> hashMap=new HashMap<>();
        hashMap.put("hello",1);
        hashMap.put("hi",2);
        for(Map.Entry<String,Integer> a: hashMap.entrySet())
        {
            System.out.println(a.getKey());
            System.out.println(a.getValue());
        }

HashMap<String,Integer> hashMap=new HashMap<>();
        hashMap.put("hello",1);
        hashMap.put("hi",2);
        Iterator<Map.Entry<String,Integer>> iterator=hashMap.entrySet().iterator();
        while(iterator.hasNext())
        {
            Map.Entry<String,Integer> a=iterator.next();
            System.out.println(a.getKey()+a.getValue());
        }