java - 如何在java中的arraylist中获取随时间升序的日期

Question

我有一个日期列表，例如:

20-aug-2018 05:34 pm, 20-aug-2018 06:23 pm, 20-aug-2018 04:03 pm, 20-aug-2018 07:20 pm

现在我想得到这样的输出:

20-aug-2018 04:03 pm, 20-aug-2018 05:34 pm, 20-aug-2018 06:23 pm, 20-aug-2018 07:20 pm

Answer 1

如果输入是List<String> ，你可以这样实现:

1. 将日期字符串解析为 LocalDateTime

2. LocalDateTime具有可比性，只需调用list.sort

示例代码:

// initiate input
List<String> list = new ArrayList<>(Arrays.asList("20-aug-2018 05:34 pm", "20-Aug-2018 06:23 pm", "20-aug-2018 04:03 pm", "20-aug-2018 07:20 pm"));

// build a formatter which is used to parse the string to LocalDateTime
DateTimeFormatter formatter = new DateTimeFormatterBuilder()
        .parseCaseInsensitive()
        .appendPattern("dd-MMM-yyyy hh:mm a")
        .toFormatter(Locale.US);

// sort based on LocalDateTime
list.sort(Comparator.comparing(dateString -> LocalDateTime.parse(dateString, formatter)));
System.out.println(list);

输出:

[20-aug-2018 04:03 pm, 20-aug-2018 05:34 pm, 20-Aug-2018 06:23 pm, 20-aug-2018 07:20 pm]