33.Map

        HashMap<String, String> hashMap = new HashMap<>();
        hashMap.put("001","张飞");
        hashMap.put("002","关于");
        hashMap.put("003","赵云");
        Set<String> stringSet = hashMap.keySet();
        for (String key:stringSet){
            System.out.println(key+":"+hashMap.get(key));
        }

        Set<Map.Entry<String, String>> entries = hashMap.entrySet();
        for (Map.Entry<String, String> m:entries){
            System.out.println(m.getKey()+":"+m.getValue());
        }