如何使用Java 8库将UTC日期时间转换为另一个时区? [英] How to convert UTC DateTime to another Time Zone using Java 8 library?

问题描述

final Timestamp rawDateTime = Timestamp.valueOf("2031-04-25 18:30:00");
final ZoneId zoneId = ZoneId.of("Asia/Calcutta");
final ZonedDateTime zonedDateTime = ZonedDateTime.ofInstant(
    Instant.ofEpochMilli(rawDateTime.getTime()), zoneId); 
// here we are getting output as 2031-04-25T18:30+05:30[Asia/Calcutta]

final ZonedDateTime zonedDateTime1 = 
ZonedDateTime.of(rawDateTime.toLocalDateTime(), zoneId);
// here we are getting output as 2031-04-25T18:30+05:30[Asia/Calcutta]

但是我想将转换后的日期时间设为2031-04-26 00:00:00 + 5:30，因为我的时间戳记值位于UTC时区.

请帮助.

解决方案

首先，您不应该使用Timestamp.您可以使用 DateTimeFormatter 来解析为 LocalDateTime .

然后将LocalDateTime分区为UTC，然后使用

final Timestamp rawDateTime = Timestamp.valueOf("2031-04-25 18:30:00");
final ZoneId zoneId = ZoneId.of("Asia/Calcutta");
final ZonedDateTime zonedDateTime = ZonedDateTime.ofInstant(
    Instant.ofEpochMilli(rawDateTime.getTime()), zoneId); 
// here we are getting output as 2031-04-25T18:30+05:30[Asia/Calcutta]

final ZonedDateTime zonedDateTime1 = 
ZonedDateTime.of(rawDateTime.toLocalDateTime(), zoneId);
// here we are getting output as 2031-04-25T18:30+05:30[Asia/Calcutta]

But I want to get the converted date time as 2031-04-26 00:00:00+5:30 as my timestamp value is in the UTC Timezone.

Please help.

解决方案

First, you should not use Timestamp. You can use DateTimeFormatter to parse into a LocalDateTime.

You then zone that LocalDateTime to UTC before converting to the Calcutta zone with ZonedDateTime.withZoneSameInstant.

DateTimeFormatter formatter = new DateTimeFormatterBuilder()
    .append(DateTimeFormatter.ISO_LOCAL_DATE)
    .appendLiteral(' ')
    .append(DateTimeFormatter.ISO_LOCAL_TIME)
    .toFormatter();

LocalDateTime localDateTime = LocalDateTime.parse("2031-04-25 18:30:00", formatter);
ZoneId calcuttaZone = ZoneId.of("Asia/Calcutta");
ZonedDateTime calcuttaZonedDateTime = localDateTime.atZone(ZoneOffset.UTC)
    .withZoneSameInstant(calcuttaZone);

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