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andrea 2018-03-11 21:35:00 +01:00
parent b63caab397
commit c5ac4b4bba
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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)==3600000);
assertThat(cal.get(Calendar.DST_OFFSET)==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)==3600000);
assertThat(dateAfterDST == df.parse("2018-03-25 03:05"));
Long deltaBetweenDatesInMillis = dateAfterDST.getTime() - dateBeforeDST.getTime();
Long seventyMinutesInMillis = (1000L * 60 * 70);
assertThat(deltaBetweenDatesInMillis == seventyMinutesInMillis);
}
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);
}
}
}