解析日期时间字符串中日期的序数指示符( st, nd, rd, th ) [英] Parsing a date’s ordinal indicator ( st, nd, rd, th ) in a date-time string

问题描述

我检查了 SimpleDateFormat javadoc，但我找不到解析序数指标的方法a> 以这样的日期格式:

I checked the SimpleDateFormat javadoc, but I am not able to find a way to parse the ordinal indicator in a date format like this:

 Feb 13th 2015 9:00AM

我尝试了 "MMM dd yyyy hh:mma"，但是天数必须很多才能正确?

I tried "MMM dd yyyy hh:mma", but the days have to be in number for it to be correct?

是否可以使用 SimpleDateFormat 解析第 13 个"日期而不必截断字符串?

Is it possible to parse the "13th" date using a SimpleDateFormat without having to truncate the string?

推荐答案

Java 的 SimpleDateFormat 不支持序数后缀，但序数后缀只是令人赏心悦目的 - 它是多余的并且可以轻松删除以允许直接解析:

Java's SimpleDateFormat doesn't support an ordinal suffix, but the ordinal suffix is just eye candy - it is redundant and can easily be removed to allow a straightforward parse:

Date date = new SimpleDateFormat("MMM dd yyyy hh:mma")
    .parse(str.replaceAll("(?<=\d)(st|nd|rd|th)", ""));

替换正则表达式非常简单，因为这些序列不会出现在有效日期的其他任何地方.

The replace regex is so simple because those sequences won't appear anywhere else in a valid date.

处理将任何语言的任何长度的序数指示字符作为后缀的任何语言:

To handle any language that appends any length of ordinal indicator characters from any language as a suffix:

Date date = new SimpleDateFormat("MMM dd yyyy hh:mma")
    .parse(str.replaceAll("(?<=\d)(?=\D* \d+ )\p{L}+", ""));

某些语言，例如普通话，在它们的序数指示符之前，但这也可以使用交替来处理 - 留给读者练习:)

Some languages, eg Mandarin, prepend their ordinal indicator, but that could be handled too using an alternation - left as an exercise for the reader :)

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