无法解析最近格式化的ZonedDateTime Java 8 [英] Cant parse recently formatted ZonedDateTime Java 8

问题描述

为什么使用此代码

DateTimeFormatter SENT_DATE_FORMATTER = DateTimeFormatter.ofPattern("E, d MMM YYYY HH:mm:ss Z", Locale.US);
ZonedDateTime now = ZonedDateTime.now();
String dateStr = now.format(SENT_DATE_FORMATTER);
System.out.println(dateStr);

ZonedDateTime zoned = ZonedDateTime.parse(dateStr, SENT_DATE_FORMATTER);

在sysout行上打印正确的日期，但抛出DateTimeParseException（无法从TemporalAccessor获取ZonedDateTime）

Prints the correct date on the sysout line but throws a DateTimeParseException (Unable to obtain ZonedDateTime from TemporalAccessor) on the parse line?

推荐答案

大写的Y代表基于周的年，请参见 javadoc 。为了使解析器正常工作，您需要将其更改为年份（u）或时代（y）。然后，解析器可以创建日历年，月（M）和月日（d）之外的日期。请记住，以周为基础的年份可以与上一个或下一个日历年相关，如果您的月份和日期接近日历年的开始或结束，则不是实际的年份。因此，不可能仅将基于周的年份与日历年份相等！ 并且没有精确定义的日历年，就无法形成日期。

Capitalized Y stands for week-based-year, see javadoc. In order to make the parser working you rather need to change it to year (u) or year-of-era (y). Then the parser can create a date out of calendar year, month (M) and day-of-month (d). Keep in mind that the week-based-year can relate to previous or next calendar year, not the actual one if your month and day-of-month are near the start or end of calendar year. Therefore it is not possible to just equalize the week-based-year to the calendar year! And without a precisely defined calendar year it is not possible to form a date.

否则，如果您有星期几，基于模式的年（w），那么解析器将能够理解输入，因为基于周的年（Y），基于周的周年（w）和周中的某天（E）还会对日期进行可解释的组合。

Otherwise, if you had the week-of-week-based-year (w) in your pattern, too, then your parser would be able to understand the input because week-based-year (Y), week-of-week-based-year (w) and day-of-week (E) would also make an interpretable combination for a date.

但是请注意，输入中与您的模式匹配的所有给定细节必须一致（例如2015-08 -31是星期一，而不是星期二），否则解析器会再次抱怨（至少在严格模式下如此）。

Note however, that all given details in the input matching your pattern must be consistent (for example 2015-08-31 is Monday and not Tuesday) otherwise the parser will complain again (at least in strict mode).

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