public static void main(String[] args) {
Map<String, Integer> map = new HashMap();
map.put("13213", 8);
Set<String> set=map.keySet();
map.entrySet();
List<Map.Entry<String,Integer>> list = new ArrayList(map.entrySet());
Collections.sort(list, (o1, o2) -> (o2.getValue() - o1.getValue()));//升序
System.out.println(list.get(0).getKey());
}
