diff --git a/core-java-8/src/test/java/com/baeldung/datetime/UseTimeZoneUnitTest.java b/core-java-8/src/test/java/com/baeldung/datetime/UseTimeZoneUnitTest.java new file mode 100644 index 0000000000..4423ac6ce0 --- /dev/null +++ b/core-java-8/src/test/java/com/baeldung/datetime/UseTimeZoneUnitTest.java @@ -0,0 +1,72 @@ +package com.baeldung.datetime; + +import java.text.SimpleDateFormat; +import java.time.Instant; +import java.time.ZoneId; +import java.time.ZonedDateTime; +import java.time.format.DateTimeFormatter; +import java.util.Calendar; +import java.util.Date; +import java.util.TimeZone; + +import org.joda.time.DateTime; +import org.joda.time.DateTimeZone; +import org.junit.Assert; +import org.junit.Test; + +public class UseTimeZoneUnitTest { + + /* https://en.wikipedia.org/wiki/List_of_tz_database_time_zones */ + + String timeZone = "Asia/Singapore"; + + private static final String PATTERN = "E yyyy-MM-dd HH:mm:ss a"; + + @Test + public void givenDateWithoutTimeZone_WhenSetTimeZoneUsingJava7_ThenTimeZoneIsSetSuccessfully() { + Date nowUtc = new Date(); + TimeZone asiaSingapore = TimeZone.getTimeZone(timeZone); + + Calendar nowAsiaSingapore = Calendar.getInstance(asiaSingapore); + nowAsiaSingapore.setTime(nowUtc); + + SimpleDateFormat simpleDateFormat = new SimpleDateFormat(PATTERN); + simpleDateFormat.setTimeZone(TimeZone.getTimeZone(timeZone)); + + System.out.println(String.format("Java7: Time now in '%s' is '%s'", nowAsiaSingapore.getTimeZone() + .getID(), simpleDateFormat.format(nowAsiaSingapore.getTime()))); + + Assert.assertEquals(nowUtc.toInstant().getEpochSecond(), nowAsiaSingapore.toInstant().getEpochSecond()); + Assert.assertEquals(asiaSingapore, nowAsiaSingapore.getTimeZone()); + + } + + @Test + public void givenDateWithoutTimeZone_WhenSetTimeZoneUsingJava8_ThenTimeZoneIsSetSuccessfully() { + Instant nowUtc = Instant.now(); + ZoneId asiaSingapore = ZoneId.of(timeZone); + + ZonedDateTime nowAsiaSingapore = ZonedDateTime.ofInstant(nowUtc, asiaSingapore); + + System.out.println(String.format("Java8: Time now in '%s' is '%s'", nowAsiaSingapore.getZone(), + nowAsiaSingapore.format(DateTimeFormatter.ofPattern(PATTERN)))); + + Assert.assertEquals(nowUtc.getEpochSecond(), nowAsiaSingapore.toEpochSecond()); + Assert.assertEquals(asiaSingapore, nowAsiaSingapore.getZone()); + } + + @Test + public void givenDateWithoutTimeZone_WhenSetTimeZoneUsingJodaTime_ThenTimeZoneIsSetSuccessfully() { + org.joda.time.Instant nowUtc = org.joda.time.Instant.now(); + DateTimeZone asiaSingapore = DateTimeZone.forID(timeZone); + + DateTime nowAsiaSingapore = nowUtc.toDateTime(asiaSingapore); + + System.out.println(String.format("Joda-time: Time now in '%s' is '%s'", nowAsiaSingapore.getZone(), + nowAsiaSingapore.toString(PATTERN))); + + Assert.assertEquals(nowUtc.toInstant().getMillis(), nowAsiaSingapore.toInstant().getMillis()); + Assert.assertEquals(asiaSingapore, nowAsiaSingapore.getZone()); + } + +}