如何在 Java 中将 ZonedDateTime 转换为 milliSecond？
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How to convert ZonedDateTime to milliSecond in Java?
提问by Arun
I'm trying to convert ZonedDateTime to milliseconds using below code.
我正在尝试使用以下代码将 ZonedDateTime 转换为毫秒。
LocalDateTime ldt = LocalDateTime.now();
ZonedDateTime zonedDateTime =ldt.atZone(ZoneId.of(""Asia/Kolkata""));
zonedDateTime.toInstant().toEpochMilli();
But this one returns milliseconds based on local time. And it's not considering ZoneId.
但是这个根据本地时间返回毫秒。它没有考虑 ZoneId。
Let's say LocalDateTime("2019-04-10T05:30"). If I convert this to ZonedDateTimewith Zone id ("Asia/Kolkata") then I'm getting ("2019-04-10T05:30+05:30[Asia/Kolkata]"). Then I convert to EpochMilli (1554854400000) = ("Wed Apr 10 2019 00:00:00") in UTC.
让我们说LocalDateTime("2019-04-10T05:30")。如果我将其转换为ZonedDateTimeZone id ("Asia/Kolkata") 那么我得到 ( "2019-04-10T05:30+05:30[Asia/Kolkata]")。然后我"Wed Apr 10 2019 00:00:00"在UTC转换为EpochMilli (1554854400000) = ( ) 。
采纳答案by AxelH
You are using an Instantto get that milliseconds representation. Instant are not zone based. Now, the epoch time is based on the "1970-01-01T00:00:00Z" so you should not have the zone in it.
您正在使用 anInstant来获取毫秒表示。Instant 不是基于区域的。现在，纪元时间基于“1970-01-01T00:00:00Z”，因此您不应该在其中包含该区域。
If you want to create a ZoneDateTimefrom the epoch value, you can simply create an Instantat that epoch time and then create a ZonedDateTimewith the zone you wish :
如果你想ZoneDateTime从纪元值创建一个，你可以简单地Instant在那个纪元时间创建一个ZonedDateTime，然后用你想要的区域创建一个：
//Let's create our zone time (just to keep your logic
LocalDateTime ldt = LocalDateTime.now();
ZonedDateTime zonedDateTime =ldt.atZone(ZoneId.of("Asia/Kolkata"));
//Then get the epoch on GMT
long e = zonedDateTime.toInstant().toEpochMilli();
Instant i = Instant.ofEpochMilli(e);
System.out.println(ZonedDateTime.ofInstant(i, ZoneId.systemDefault()));
System.out.println(ZonedDateTime.ofInstant(i, ZoneId.of("Asia/Kolkata")));
2019-04-12T05:10:31.016+02:00[Europe/Paris]
2019-04-12T08:40:31.016+05:30[Asia/Kolkata]
2019-04-12T05:10:31.016+02:00[欧洲/巴黎]
2019-04-12T08:40:31.016+05:30[亚洲/加尔各答]
NOTE : The code above should not be used like this, it is not necessary to get a LocalDateTimethen a ZonedDateTimeto finally create an Instant. This is just to show that even with a zone, this will be "lost" at one point.
Simply use :
注意：上面的代码不应该这样使用，没有必要得到一个LocalDateTimethen aZonedDateTime来最终创建一个Instant. 这只是为了表明即使有一个区域，它也会在某一时刻“丢失”。
只需使用：
long e = Instant.now().toEpochMilli();
