I am currently writing an application where I need to check if there were any files created before yesterday and clean them up. At the moment when I try the below:
LocalDateTime today = LocalDate.now().atStartOfDay();
long todayEpoch = today.atZone(ZoneId.of("Europe/London")).toEpochSecond() * 1000;
and convert the milliseconds back to a Date (on any online millisecond to date converter) it tells me I am 1 hour behind.
This is because of Daylight Savings Time, which means we are GMT+1:00 which probably explains the 1 hour difference.
To solve this I had to do change the Zone Id to UTC as below:
final LocalDateTime today = LocalDate.now().atStartOfDay();
long todayEpoch = today.atZone(ZoneId.of("UTC")).toEpochSecond() * 1000;
But I am still confused how it worked.
Can someone explain why?
答案 0 :(得分：1)
dplyr今天（在您的时区）00:00返回。因此，如果今天是2016年6月10日，则会返回LocalDateTime today = LocalDate.now().atStartOfDay();
。
2016-06-10 00:00将时区信息添加到日期，由于英国夏令时，该日期变为：today.atZone(ZoneId.of("Europe/London"))
，与2016-06-10 00:00 Europe/London的时刻相同。
然后检索纪元秒数，这是1970年1月1日00:00 UTC与该时刻之间经过的秒数。
在第二个示例中，您计算了纪元与2016-06-09 23:00 UTC或2016-06-10 01:00 Europe/London之间的毫秒数。
你需要决定你想要的。