Java HashMap 按键插入时间排序-创意顺序

Question

我想按创意顺序对 hashmap 进行排序或将所有键添加到 arraylist 例如：

        HashMap<String, String> map_from_file = new HashMap<String, String>();
        map_from_file.put("C", "c");
        map_from_file.put("B", "b");
        map_from_file.put("D", "d");
        map_from_file.put("A", "a");


        for (String key : map_from_file.keySet()) {
            System.out.println(key);
        }

输出：

A
B
C
D

我希望输出为：

C
B
D
A

感谢您的帮助

Answer 1

Map<String, String> map_from_file = new LinkedHashMap<>();
        map_from_file.put("C", "c");
        map_from_file.put("B", "b");
        map_from_file.put("D", "d");
        map_from_file.put("A", "a");


        for (String key : map_from_file.keySet()) {
            System.out.println(key);
        }

Answer 2

您必须对有序键使用 LinkedHashMap 数据结构。

Java HashMap 按键插入时间排序-创意顺序

Java HashMap sorted by key insertion time - creative order

java

hashmap