Java 8 将给定的时间和时区转换为 UTC 时间
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Java 8 Convert given time and time zone to UTC time
提问by ttt
I have a time with string type like: "2015-01-05 17:00"and ZoneIdis "Australia/Sydney".
我有一段时间使用字符串类型，例如："2015-01-05 17:00"and ZoneIdis "Australia/Sydney"。
How can I convert this time information to the corresponding to UTC time using Java 8 datetime API?
如何使用 Java 8 datetime API 将此时间信息转换为对应的 UTC 时间？
Also need to considering DST stuff.
还需要考虑夏令时的东西。
采纳答案by Mateusz Sroka
You are looking for ZonedDateTimeclass in Java8 - a complete date-time with time-zone and resolved offset from UTC/Greenwich. In terms of design, this class should be viewed primarily as the combination of a LocalDateTimeand a ZoneId. The ZoneOffsetis a vital, but secondary, piece of information, used to ensure that the class represents an instant, especially during a daylight savings overlap.
您正在寻找ZonedDateTimeJava8中的类 - 一个完整的日期时间与时区和已解决的 UTC/格林威治偏移量。在设计方面，这个类应该主要被视为 aLocalDateTime和 a的组合ZoneId。这ZoneOffset是一个至关重要但次要的信息，用于确保该类代表一个瞬间，尤其是在夏令时重叠期间。
For example:
例如：
ZoneId australia = ZoneId.of("Australia/Sydney");
String str = "2015-01-05 17:00";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm");
LocalDateTime localtDateAndTime = LocalDateTime.parse(str, formatter);
ZonedDateTime dateAndTimeInSydney = ZonedDateTime.of(localtDateAndTime, australia );
System.out.println("Current date and time in a particular timezone : " + dateAndTimeInSydney);
ZonedDateTime utcDate = dateAndTimeInSydney.withZoneSameInstant(ZoneOffset.UTC);
System.out.println("Current date and time in UTC : " + utcDate);
回答by assylias
An alternative to the existing answer is to setup the formatter with the appropriate time zone:
现有答案的替代方法是使用适当的时区设置格式化程序：
String input = "2015-01-05 17:00";
ZoneId zone = ZoneId.of("Australia/Sydney");
DateTimeFormatter fmt = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm").withZone(zone);
ZonedDateTime utc = ZonedDateTime.parse(input, fmt).withZoneSameInstant(UTC);
Since you want to interact with a database, you may need a java.sql.Timestamp, in which case you don't need to explicitly convert to a UTC time but can use an Instant instead:
由于您想与数据库交互，您可能需要一个java.sql.Timestamp，在这种情况下，您不需要显式转换为 UTC 时间，而是可以使用 Instant ：
ZonedDateTime zdt = ZonedDateTime.parse(input, fmt);
Timestamp sqlTs = Timestamp.from(zdt.toInstant());
回答by Mukesh
**// Refactored Logic**
ZoneId australia = ZoneId.of("Australia/Sydney");
ZoneId utcZoneID= ZoneId.of("Etc/UTC");
String ausTime = "2015-01-05 17:00";
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm");
//converting in datetime of java8
LocalDateTime ausDateAndTime = LocalDateTime.parse(ausTime, formatter);
// DateTime With Zone
ZonedDateTime utcDateAndTime = ausDateAndTime.atZone(utcZoneID);
// output - 2015-01-05T17:00Z[Etc/UTC]
// With Formating DateTime
String utcDateTime = utcDateAndTime.format(formatter);
// output - 2015-01-05 17:00
