java8 lambda表达式 Map排序

public static void main(String[] args) {
        Map<String, Integer> map = new HashMap<>();
        map.put("id", 4);
        map.put("name", 1);
        map.put("sex", 3);
        map.put("age", 2);
        //根据value正序
        Map<String, Integer> result1 = map.entrySet().stream().
                sorted(Map.Entry.comparingByValue())
                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue,
                        (oldValue, newValue) -> oldValue, LinkedHashMap::new));
        //根据value倒序
        Map<String, Integer> result2 = map.entrySet().stream().
                sorted(Map.Entry.comparingByValue(Comparator.reverseOrder()))
                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue,
                        (oldValue, newValue) -> oldValue, LinkedHashMap::new));
        //根据key正序
        Map<String, Integer> result3 = map.entrySet().stream().
                sorted(Map.Entry.comparingByKey())
                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue,
                        (oldValue, newValue) -> oldValue, LinkedHashMap::new));
        //根据key倒序
        Map<String, Integer> result4 = map.entrySet().stream().
                sorted(Map.Entry.comparingByKey(Comparator.reverseOrder()))
                .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue,
                        (oldValue, newValue) -> oldValue, LinkedHashMap::new));
        System.out.println(result1);
        System.out.println(result2);
        System.out.println(result3);
        System.out.println(result4);
    }

输出结果

{name=1, age=2, sex=3, id=4}
{id=4, sex=3, age=2, name=1}
{age=2, id=4, name=1, sex=3}
{sex=3, name=1, id=4, age=2}
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转载自blog.csdn.net/qq_40977118/article/details/104565697