如何将Instant转换为LocalTime?

问题描述

即使阅读了许多教程，我还是不太了解TemporalAdjusters或Java的新时间库.

I don't really understand TemporalAdjusters or Java's new time library even after reading numerous tutorials.

如何将 Instant 对象转换为 LocalTime 对象.我正在按照以下思路进行思考:

How can I convert an Instant object to a LocalTime object. I was thinking something along the lines of the following:

LocalTime time = LocalTime.of(
    instantStart.get(ChronoField.HOUR_OF_DAY),
    instantStart.get(ChronoField.MINUTE_OF_HOUR)
);

但是它不起作用.我该怎么办?

But it isn't working. How can I do this?

推荐答案

我的理解方式... Instant是UTC风格的时间，与区域始终UTC无关.LocalTime是与给定区域无关的时间.因此，如果 Instant 实现了 TemporalAccessor ，

The way I understand it... Instant is a UTC style time, agnostic of zone always UTC. LocalTime is a time independent of given zone. So you'd expect the following would work given that Instant implements TemporalAccessor,

Instant instant = Instant.now();
LocalTime local =  LocalTime.from(instant);

，但是您收到无法从TemporalAccessor获取LocalTime"错误.相反，您需要说明本地"的位置.是.没有默认值-可能是一件好事.

but you get "Unable to obtain LocalTime from TemporalAccessor" error. Instead you need to state where "local" is. There is no default - probably a good thing.

Instant instant = Instant.now();
LocalTime local =  LocalTime.from(instant.atZone(ZoneId.of("GMT+3")));
System.out.println(String.format("%s => %s", instant, local));

输出

2014-12-07T07:52:43.900Z => 10:52:43.900

instantStart.get(ChronoField.HOUR_OF_DAY)抛出错误，因为它在概念上不支持它，您只能通过LocalTime实例访问HOUR_OF_DAY等.

instantStart.get(ChronoField.HOUR_OF_DAY) throws an error because it does not conceptually support it, you can only access HOUR_OF_DAY etc. via a LocalTime instance.

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