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Merge pull request #3872 from andrea-ligios/master 

BAEL-1599
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Loredana Crusoveanu 2018-03-23 19:10:32 +02:00 committed by GitHub
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60
core-java/src/test/java/com/baeldung/dst/DaylightSavingTimeExamplesTest.java Normal file
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package com.baeldung.dst;
import static org.assertj.core.api.Assertions.assertThat;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;
import java.util.TimeZone;
import org.junit.Test;
public class DaylightSavingTimeExamplesTest {
@Test
public void givenItalianTimeZone_WhenDSTHappens_ThenCorrectlyShiftTimeZone() throws ParseException {
TimeZone tz = TimeZone.getTimeZone("Europe/Rome");
Calendar cal = Calendar.getInstance(tz, Locale.ITALIAN);
DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm", Locale.ITALIAN);
Date dateBeforeDST = df.parse("2018-03-25 01:55");
prettyPrint(cal.getTimeZone());
cal.setTime(dateBeforeDST);
System.out.println("Before DST (00:55 UTC - 01:55 GMT+1) = " + dateBeforeDST);
System.out.println("With this Calendar " + (cal.get(Calendar.ZONE_OFFSET) + cal.get(Calendar.DST_OFFSET)) / (60 * 1000) + " minutes must be added to UTC (GMT TimeZone) to get a correct date for this TimeZone\n");
assertThat(cal.get(Calendar.ZONE_OFFSET)).isEqualTo(3600000);
assertThat(cal.get(Calendar.DST_OFFSET)).isEqualTo(0);
cal.add(Calendar.MINUTE, 10);
Date dateAfterDST = cal.getTime();
System.out.println(" After DST (01:05 UTC - 03:05 GMT+2) = " + dateAfterDST);
System.out.println("With this Calendar " + (cal.get(Calendar.ZONE_OFFSET) + cal.get(Calendar.DST_OFFSET)) / (60 * 1000) + " minutes must be added to UTC (GMT TimeZone) to get a correct date for this TimeZone\n");
assertThat(cal.get(Calendar.DST_OFFSET)).isEqualTo(3600000);
assertThat(dateAfterDST).isEqualTo(df.parse("2018-03-25 03:05"));
Long deltaBetweenDatesInMillis = dateAfterDST.getTime() - dateBeforeDST.getTime();
Long tenMinutesInMillis = (1000L * 60 * 10);
assertThat(deltaBetweenDatesInMillis).isEqualTo(tenMinutesInMillis);
}
private void prettyPrint(TimeZone tz) {
System.out.println(String.format(
" Zone ID = %s (%s)\n"
+ " RawOffset = %s minutes\n"
+ " DST = %s minutes\n"
+ " -----------------------------------------",
tz.getID(), tz.getDisplayName(), tz.getRawOffset()/60000, tz.getDSTSavings()/60000));
}
@Test
public void whenIterating_ThenPrintAllTimeZones() {
for (String id : TimeZone.getAvailableIDs()) {
TimeZone tz = TimeZone.getTimeZone(id);
prettyPrint(tz);
}
}
}

52
core-java/src/test/java/com/baeldung/dst/DaylightSavingTimeJavaTimeExamplesTest.java Normal file
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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 DaylightSavingTimeJavaTimeExamplesTest {
@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) {
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));
}
@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);
}
}