java.util.concurrent.TimeUnit represents time durations in Java at a given unit of granularity and provides utility methods to convert across units. java.util.concurrent.TimeUnit was introduced back in the old Java days (1.5) but since then it has been extended several times already. In this blog post you will learn how to use java.util.concurrent.TimeUnit to convert a given time unit to a duration .
Prerequisites
You will need JDK 11+ for the examples to work.
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Problem
Convert a given time unit to duration in Java
Solution
Use java.concurrent.TimeUnit enum.
Java 11
TimeUnit.convert(Duration duration):
1 2 3 | long yearInMillis = TimeUnit.MILLISECONDS.convert(Duration.ofDays(365));long hourInMillis = TimeUnit.MILLISECONDS.convert(Duration.ofHours(1));long minuteInMillis = TimeUnit.MILLISECONDS.convert(Duration.ofMinutes(1)); |
TimeUnit.convert(Duration duration)withjava.time.ChronoUnit:
1 2 3 | long yearInMillis = TimeUnit.MILLISECONDS.convert(Duration.of(365, TimeUnit.DAYS.toChronoUnit()));long hourInMillis = TimeUnit.MILLISECONDS.convert(Duration.of(1, TimeUnit.HOURS.toChronoUnit()));long minuteInMillis = TimeUnit.MILLISECONDS.convert(Duration.of(1, TimeUnit.MINUTES.toChronoUnit())); |
Pre-Java 11
- Generic
TimeUnit.convert(long sourceDuration, TimeUnit sourceUnit)
1 2 3 | long yearInMillis = TimeUnit.DAYS.toMillis(365);long hourInMillis = TimeUnit.HOURS.toMillis(1);long minuteInMillis = TimeUnit.MINUTES.toMillis(1); |
TimeUnit.toMillis(long duration),TimeUnit.toSeconds(long duration)etc. methods:
1 2 3 | long yearInMillis = TimeUnit.MILLISECONDS.convert(365, TimeUnit.DAYS);long hourInMillis = TimeUnit.MILLISECONDS.convert(1, TimeUnit.HOURS);long minuteInMillis = TimeUnit.MILLISECONDS.convert(1, TimeUnit.MINUTES); |
Final example
01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 | class Java11TimeUnitConvertTests { public static final long DAYS_IN_A_YEAR = 365L; public static final long HOURS_IN_A_DAY = 24L; public static final long MINUTES_IN_AN_HOUR = 60L; public static final long SECONDS_IN_A_MINUTE = 60L; public static final long MILLISECONDS_IN_A_SECOND = 1000L; @Test void aYearInMillis() { // A year in milliseconds long yearInMillis = TimeUnit.MILLISECONDS.convert(Duration.ofDays(365)); // since Java 11 assertThat(yearInMillis) .isEqualTo(DAYS_IN_A_YEAR * HOURS_IN_A_DAY * MINUTES_IN_AN_HOUR * SECONDS_IN_A_MINUTE * MILLISECONDS_IN_A_SECOND) .isEqualTo(TimeUnit.DAYS.toMillis(365)) .isEqualTo(TimeUnit.MILLISECONDS.convert(365, TimeUnit.DAYS)) .isEqualTo(TimeUnit.MILLISECONDS.convert(Duration.of(365, TimeUnit.DAYS.toChronoUnit()))); // since Java 11 } @Test void anHourInMillis() { long hourInMillis = TimeUnit.MILLISECONDS.convert(Duration.ofHours(1)); // since Java 11 assertThat(hourInMillis) .isEqualTo(MINUTES_IN_AN_HOUR * SECONDS_IN_A_MINUTE * MILLISECONDS_IN_A_SECOND) .isEqualTo(TimeUnit.HOURS.toMillis(1)) .isEqualTo(TimeUnit.MILLISECONDS.convert(1, TimeUnit.HOURS)) .isEqualTo(TimeUnit.MILLISECONDS.convert(Duration.of(1, TimeUnit.HOURS.toChronoUnit()))); // since Java 11 } @Test void aMinuteInMillis() { long minuteInMillis = TimeUnit.MILLISECONDS.convert(Duration.ofMinutes(1)); // since Java 11 assertThat(minuteInMillis) .isEqualTo(SECONDS_IN_A_MINUTE * MILLISECONDS_IN_A_SECOND) .isEqualTo(TimeUnit.MINUTES.toMillis(1)) .isEqualTo(TimeUnit.MILLISECONDS.convert(1, TimeUnit.MINUTES)) .isEqualTo(TimeUnit.MILLISECONDS.convert(Duration.of(1, TimeUnit.MINUTES.toChronoUnit()))); // since Java 11 } @ParameterizedTest @MethodSource("timeUnitToDuration") void convertTimeUnitToDuration(TimeUnit unit, Duration duration, long expectedResult) { long actualResult = unit.convert(duration); assertThat(actualResult).isEqualTo(expectedResult); } private static Stream<Arguments> timeUnitToDuration() { return Stream.of( Arguments.of(TimeUnit.DAYS, Duration.ofHours(24), 1), // 24h = 1d Arguments.of(TimeUnit.DAYS, Duration.ofHours(40), 1), // 40h = 1d Arguments.of(TimeUnit.DAYS, Duration.ofHours(48), 2), // 48h = 2d Arguments.of(TimeUnit.DAYS, Duration.ofHours(50), 2), // 50h = 2d Arguments.of(TimeUnit.MILLISECONDS, Duration.ofSeconds(1), 1000), // 1s = 1000ms Arguments.of(TimeUnit.MILLISECONDS, Duration.ofSeconds(11), 11000), // 1s = 11000ms Arguments.of(TimeUnit.SECONDS, Duration.ofHours(1), 3600), // 1h = 3600s Arguments.of(TimeUnit.HOURS, Duration.ofSeconds(4_000), 1), // 4000s = 1h Arguments.of(TimeUnit.HOURS, Duration.ofSeconds(1_0000), 2) // 10000s = 2h ); }} |
Source code
The source code for this article can be found on Github: https://github.com/kolorobot/java9-and-beyond
Published on Java Code Geeks with permission by Rafal Borowiec, partner at our JCG program. See the original article here: Convert time unit to duration in Java Opinions expressed by Java Code Geeks contributors are their own. |
