什么是处理时区经常变化的最佳实践

Question

I'm writing a toy logistics service. As a result, products will travel through lots of different timezones, and I'll need to query both the strict ordering of events, as well as what hour of day it is for products (for example, what happened when the sun was at its hottest, at 1200).

At the moment, I'm saving jodatime DateTimes and trying to deal with them exclusively, but I know time is mighty tricky, and I'm wondering if I need to do anything else to make sure it all works.

Answer 1

Given that you're recording events as they occur (rather than planning for future events), you probably don't need to worry about changes to time zone rules which occur in the future.

As such, it would be reasonable to store a timestamp (eg as UTC) and also the time zone ID for the location of the event. To make querying easier, you could also store the local time at the time of the event. Just be aware that as a toy is travelling through time zones, there could be multiple events at different instants in time, all of which occur at "midday" on the same day (but in different zones). You really need to think carefully about what queries you really want to perform on the local date/time values.

Answer 2

I am not familiar with jodatime but when I need to store the time I always enjoy using Epoch time because it is very easy to manipulate to get different formats. If you're interested in it here is a converter website that I find very helpful: http://www.epochconverter.com/