如何转换日期值“2017年5月26日”至“26/05 / 2017”？ [英] How to convert the date value "26th May 2017" to "26/05/2017"?

问题描述

是否有任何java库可用于解析语言特定的序数指示符/后缀？

Is there any java library available to parse language specific ordinal indicator/suffix?

我有如下日期值： 5月26日2017 。我想将其转换为 26/05/2017 。有人可以指导我怎么做吗？

I have a date value like the following: 26th May 2017. I want to convert this to 26/05/2017. Could anyone please guide me how to do?

推荐答案

你可以直接将这种格式解析为Java 8 LocalDate 使用自定义日期格式：

You can parse this format directly to a Java 8 LocalDate using a custom date format:

static final Map<Long, String> ORDINAL_DAYS = new HashMap<>();
static
 {
   ORDINAL_DAYS.put(1, "1st");
   .... more ....
   ORDINAL_DAYS.put(26, "26th");
   .... more ....
   ORDINAL_DAYS.put(31, "31st");
 }

static final DateTimeFormatter FORMAT_DAY_MONTH_YEAR = new DateTimeFormatterBuilder()
  .appendText(ChronoField.DAY_OF_MONTH, ORDINAL_DAYS)
  .appendLiteral(' ')
  .appendText(ChronoField.MONTH_OF_YEAR)
  .appendLiteral(' ')
  .appendText(ChronoField.YEAR)
  .toFormatter();


 String dateInString = "26th May 2017";

 LocalDate date = LocalDate.parse(dateInString, FORMAT_DAY_MONTH_YEAR);

这是使用 DateTimeFormatter.appendText 接受用于映射日期字符串的地图。

This is using the version of DateTimeFormatter.appendText which accepts a map that is used to map the day string.

为了简洁起见，我需要填写 ORDINAL_DAYS 中遗漏的所有条目。

You will need to fill in all the missing entries in ORDINAL_DAYS that I have left out for brevity.

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