java-tutorials/java-dates/src/test/java/com/baeldung/dst/DaylightSavingTimeJavaTimeExamplesUnitTest.java

57 lines
2.1 KiB
Java

package com.baeldung.dst;
import static org.assertj.core.api.Assertions.assertThat;
import java.text.ParseException;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.time.temporal.ChronoUnit;
import java.util.TimeZone;
import org.junit.Test;
public class DaylightSavingTimeJavaTimeExamplesUnitTest {
@Test
public void givenItalianTimeZone_WhenDSTHappens_ThenCorrectlyShiftTimeZone() throws ParseException {
ZoneId italianZoneId = ZoneId.of("Europe/Rome");
LocalDateTime localDateTimeBeforeDST = LocalDateTime.of(2018, 3, 25, 1, 55);
System.out.println(localDateTimeBeforeDST);
assertThat(localDateTimeBeforeDST.toString()).isEqualTo("2018-03-25T01:55");
ZonedDateTime zonedDateTimeBeforeDST = localDateTimeBeforeDST.atZone(italianZoneId);
prettyPrint(zonedDateTimeBeforeDST);
assertThat(zonedDateTimeBeforeDST.toString()).isEqualTo("2018-03-25T01:55+01:00[Europe/Rome]");
ZonedDateTime zonedDateTimeAfterDST = zonedDateTimeBeforeDST.plus(10, ChronoUnit.MINUTES);
prettyPrint(zonedDateTimeAfterDST);
assertThat(zonedDateTimeAfterDST.toString()).isEqualTo("2018-03-25T03:05+02:00[Europe/Rome]");
Long deltaBetweenDatesInMinutes = ChronoUnit.MINUTES.between(zonedDateTimeBeforeDST, zonedDateTimeAfterDST);
assertThat(deltaBetweenDatesInMinutes).isEqualTo(10);
}
private void prettyPrint(ZonedDateTime zdt) {
//@formatter:off
System.out.println(String.format(
" ZonedDateTime = %s\n"
+ " Zone ID = %s (%s)\n"
+ " RawOffset = %s minutes\n"
+ " -----------------------------------------",
zdt, zdt.getZone(), zdt.getZone().getId(), zdt.getOffset().getTotalSeconds()/60));
//@formatter:on
}
@Test
public void whenCounting_ThenPrintDifferencesBetweenAPIs() {
System.out.println("Total java.time.ZoneId count : " + ZoneId.getAvailableZoneIds()
.size());
System.out.println("Total java.util.TimeZone Id count : " + TimeZone.getAvailableIDs().length);
}
}