如何按降序打印HashMap值，但如果两个或多个值相等，则按键升序打印？ (爪哇)

Question

For example we have

Map<String, Integer> map = new HashMap<>();
map.put("fragments", 5);
map.put("motes", 3);
map.put("shards", 5);

I want to print them like this:

fragments: 5
shards: 5
motes: 3

Answer 1

I would solve this by first putting the values in a TreeMap

Then I would sort the keys based on equal values and put them in a LinkedHashMap to preserve the order.

      Map<String, Integer> map = new TreeMap<>();
      map.put("motes", 3);
      map.put("shards", 5);
      map.put("fragments", 5); 

      map = map.entrySet().stream().sorted(Comparator.comparing(
            Entry<String, Integer>::getValue).reversed()).collect(
                  LinkedHashMap<String, Integer>::new,
                  (map1, e) -> map1.put(e.getKey(), e.getValue()),
                  LinkedHashMap::putAll);

      map.entrySet().forEach(System.out::println);

Answer 2

Based on the excellent answer here , consider the following solution:

    public static void main(String[] args) {
        final Map<String, Integer> originalMap = new HashMap<>();
        originalMap.put("fragments", 5);
        originalMap.put("motes", 3);
        originalMap.put("shards", 5);

        final Map<String, Integer> sortedMap = sortByValue(originalMap, false);

        sortedMap
                .entrySet()
                .stream()
                .forEach((entry) -> System.out.println(entry.getKey() + " : " + entry.getValue()));

    }

    private static Map<String, Integer> sortByValue(Map<String, Integer> unsortedMap, final boolean ascending) {
        List<Entry<String, Integer>> list = new LinkedList<>(unsortedMap.entrySet());

        // Sorting the list based on values
        list.sort((o1, o2) -> ascending ? o1.getValue().compareTo(o2.getValue()) == 0
                ? o1.getKey().compareTo(o2.getKey())
                : o1.getValue().compareTo(o2.getValue()) : o2.getValue().compareTo(o1.getValue()) == 0
                ? o2.getKey().compareTo(o1.getKey())
                : o2.getValue().compareTo(o1.getValue()));
        return list.stream().collect(Collectors.toMap(Entry::getKey, Entry::getValue, (a, b) -> b, LinkedHashMap::new));

    }