Question

I got hopelessly stuck on this task. I get other-than-UTC future date input from user > I need to persist it as UTC time. I tried various ways, but it always ends up like this: (method names are irrelevant)

Could please anybody give me the right direction ?

Answer 1

It looks like you’re already doing the right thing in the first line. With slight modification:

DateTime instant = getDeadLine(orderBean, localTz);

DateTime.getMillis() will give you the number of milliseconds since the UTC epoch… so that’s what you need to persist. If you need to be able to convert back to local time, you’ll need to know which time zone to convert back to of course – either using the same one every time, or storing it along with the UTC millis.

One thing to note is that local dates/times aren’t always unambiguous – the same local date/time can occur twice due to daylight saving transitions. You’ll need to think about whether that will ever be relevant to you.