计算两个不同时区之间的时差？

Question

我想计算两个不同时区之间的时差，例如国家 1 (GMT+05:30) 和国家 2 (GMT+05:00)。如何计算。提前致谢。

Answer 1

您可以使用 java.time.Duration which is modelled on ISO-8601 standards and was introduced with Java-8 as part of JSR-310 implementation 找到它。 Java-9 引入了一些更方便的方法。

import java.time.Duration;
import java.time.LocalDate;
import java.time.OffsetDateTime;
import java.time.ZoneId;
import java.time.ZoneOffset;

public class Main {

    public static void main(String[] args) {
        // Test
        System.out.println(formatDuration(diffBetweenTimeZones("GMT+05:30", "GMT+05:00")));
        System.out.println(formatDuration(diffBetweenTimeZones("GMT+05:00", "GMT+05:30")));

        // You can use the returned value to get the ZoneOffset which you can use for
        // various kinds of processing e.g.
        ZoneOffset offset = ZoneOffset.of(formatDuration(diffBetweenTimeZones("GMT+05:30", "GMT+05:00")));
        System.out.println(offset);
        System.out.println(OffsetDateTime.now(offset));
    }

    static Duration diffBetweenTimeZones(String tz1, String tz2) {
        LocalDate today = LocalDate.now();
        return Duration.between(today.atStartOfDay(ZoneId.of(tz1)), today.atStartOfDay(ZoneId.of(tz2)));
    }

    static String formatDuration(Duration duration) {
        long hours = duration.toHours();
        long minutes = duration.toMinutes() % 60;
        String symbol = hours < 0 || minutes < 0 ? "-" : "+";
        return String.format(symbol + "%02d:%02d", Math.abs(hours), Math.abs(minutes));

        // ####################################Java-9####################################
        // return String.format(symbol + "%02d:%02d", Math.abs(duration.toHoursPart()),
        // Math.abs(duration.toMinutesPart()));
        // ####################################Java-9####################################
    }
}

输出：

+00:30
-00:30
+00:30
2021-03-24T10:37:31.056405+00:30

从 Trail: Date Time.

了解有关现代日期时间的更多信息 API

请注意 java.util 日期时间 API 已过时且容易出错。建议完全停止使用，改用modern date-time API^*.

^{* 无论出于何种原因，如果您必须坚持Java 6 或Java 7，您可以使用ThreeTen-Backport which backports most of the java.time functionality to Java 6 & 7. If you are working for an Android project and your Android API level is still not compliant with Java-8, check Java 8+ APIs available through desugaring and 。}

计算两个不同时区之间的时差？

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