HashMap分别按照key和value进行排序的快捷方法

Posted 2022-01-18 Alice_yufeng

        Map<Integer, Integer> map = new HashMap<>();
        map.put(3,3);
        map.put(2,2);
        map.put(1,6);
        map.put(6,1);

HashMap按照key排序

       Map<Integer, Integer> result = map.entrySet().stream()
                .sorted(Map.Entry.comparingByKey())
                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue,
                        (oldValue, newValue) -> oldValue, LinkedHashMap::new));
       System.out.println(result);

HasMap按照value排序

        Map<Integer, Integer> result = new LinkedHashMap<>();
        map.entrySet().stream()
                .sorted(Map.Entry.<Integer, Integer>comparingByValue().reversed())
                .forEachOrdered(x -> result.put(x.getKey(), x.getValue()));
        System.out.println(result);

参考https://www.jianshu.com/p/d9a812037d60