如何将长本地时间戳转换为字符串UTC时间戳 [英] How to convert Long local timestamp to String UTC timestamp

问题描述

这个问题非常接近我，但我发现答案不适合我。我有时间戳为长。

This question is quite close to mine, However I find the answer not suitable for me. I have timestamp as Long.

ts = 1362156863140L

因为它很长我认为它是时区天真的时间戳，是吗？这是科隆当地时间的时间戳 - UTC + 0200（CET）。因此，当我将其转换为字符串时区感知时间戳时，我想获得：

As it is Long I consider it as timezone naive timestamp, is that right? It is timestapm in local time in Cologne - UTC+0200 (CET). So when I convert it to String timezone aware timestamp I want to obtain:

2013-03-01T14:54:23.140Z

或

2013-03-01T16:54:23.140+02:00

我正在使用解决方案从我的问题开头的答案：

I'm using solution from answer in the beginning of my question:

Instant.ofEpochMilli(timestamp).atOffset(ZoneOffset.of("+2"));

返回：

2013-03-01T18:54:23.140+02:00

另一个时区：

Instant.ofEpochMilli(timestamp).atOffset(ZoneOffset.of("Z"));

返回：

2013-03-01T16:54:23.140Z

所以这些方法并不是真的更改时区，它们只是更改时间戳的表示。我还尝试了另一种方法：

So those methods does not really change the timezone, they just change representation of timestamp. I also tried another method:

OffsetDateTime.ofInstant(Instant.ofEpochMilli(timestamp), ZoneId.of("UTC"));

但结果完全相同。 此解决方案很有用，但原创方法：

But results are exactly the same. This solutions was useful, but original approach:

int offset = TimeZone.getTimeZone("Europe/Amsterdam").getRawOffset();
long newTime = timestamp - offset;

夏季/冬季时间不统一。建议的答案使用Calendar类，这对JDK8来说已经过时了。有效且显而易见的是：

does not concider summer/winter time. And suggested answers use Calendar class, which is obsolete for JDK8. What works and is obvious enough is:

OffsetDateTime.ofInstant(Instant.ofEpochMilli(Timestamp), ZoneId.of("UTC")).minusSeconds(7200);

但这不是一个正确的方法，所以我怎么能用时区做到这一点？

But it is defenetly not a proper way to do this, so how can I do that with timezone?

推荐答案

我想时间戳是 UTC ，你需要改变时间戳到 CET 。看看 withZoneSameInstant（）方法，可能会有所帮助。

I suppose that timestamp is in UTC and you need to change timestamp to CET. Take a look at withZoneSameInstant() method, might be helpful.

    long timeStamp = 1362156863140L;
    ZoneId sourceZone = ZoneId.of("UTC");
    ZoneId targetZone = ZoneId.of("CET");
    String s = ZonedDateTime.ofInstant(Instant.ofEpochMilli(timeStamp), sourceZone)
            .withZoneSameLocal(targetZone)
            .toString();
    System.out.println(s);

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