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Applied patch 27574

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When setting a cell's value to the date 2004-03-28 08:00 it is presented as
07:00 in Excel. This only happens on the days when DST starts or ends.


git-svn-id: https://svn.apache.org/repos/asf/jakarta/poi/branches/REL_2_BRANCH@353576 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Glen Stampoultzis 2004-08-04 00:43:47 +00:00
parent 2943c5a8e5
commit 95f5211037
2 changed files with 156 additions and 25 deletions
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25
src/java/org/apache/poi/hssf/usermodel/HSSFDateUtil.java
View File

@ -33,6 +33,7 @@ import java.util.GregorianCalendar;
* @author Michael Harhen * @author Michael Harhen
* @author Glen Stampoultzis (glens at apache.org) * @author Glen Stampoultzis (glens at apache.org)
* @author Dan Sherman (dsherman at isisph.com) * @author Dan Sherman (dsherman at isisph.com)
* @author Hack Kampbjorn (hak at 2mba.dk)
*/ */
public class HSSFDateUtil public class HSSFDateUtil
@ -68,9 +69,19 @@ public class HSSFDateUtil
} }
else else
{ {
// Because of daylight time saving we cannot use
// date.getTime() - calStart.getTimeInMillis()
// as the difference in milliseconds between 00:00 and 04:00
// can be 3, 4 or 5 hours but Excel expects it to always
// be 4 hours.
// E.g. 2004-03-28 04:00 CEST - 2004-03-28 00:00 CET is 3 hours
// and 2004-10-31 04:00 CET - 2004-10-31 00:00 CEST is 5 hours
double fraction = (((calStart.get(Calendar.HOUR_OF_DAY) * 60
+ calStart.get(Calendar.MINUTE)
) * 60 + calStart.get(Calendar.SECOND)
) * 1000 + calStart.get(Calendar.MILLISECOND)
) / ( double ) DAY_MILLISECONDS;
calStart = dayStart(calStart); calStart = dayStart(calStart);
double fraction = (date.getTime() - calStart.getTime().getTime())
/ ( double ) DAY_MILLISECONDS;
return fraction + ( double ) absoluteDay(calStart) return fraction + ( double ) absoluteDay(calStart)
- CAL_1900_ABSOLUTE; - CAL_1900_ABSOLUTE;
@ -96,10 +107,20 @@ public class HSSFDateUtil
* Given an Excel date with either 1900 or 1904 date windowing, * Given an Excel date with either 1900 or 1904 date windowing,
* converts it to a java.util.Date. * converts it to a java.util.Date.
* *
* NOTE: If the default <code>TimeZone</code> in Java uses Daylight
* Saving Time then the conversion back to an Excel date may not give
* the same value, that is the comparison
* <CODE>excelDate == getExcelDate(getJavaDate(excelDate,false))</CODE>
* is not always true. For example if default timezone is
* <code>Europe/Copenhagen</code>, on 2004-03-28 the minute after
* 01:59 CET is 03:00 CEST, if the excel date represents a time between
* 02:00 and 03:00 then it is converted to past 03:00 summer time
*
* @param date The Excel date. * @param date The Excel date.
* @param use1904windowing true if date uses 1904 windowing, * @param use1904windowing true if date uses 1904 windowing,
* or false if using 1900 date windowing. * or false if using 1900 date windowing.
* @return Java representation of the date, or null if date is not a valid Excel date * @return Java representation of the date, or null if date is not a valid Excel date
* @see java.util.TimeZone
*/ */
public static Date getJavaDate(double date, boolean use1904windowing) { public static Date getJavaDate(double date, boolean use1904windowing) {
if (isValidExcelDate(date)) { if (isValidExcelDate(date)) {

130
src/testcases/org/apache/poi/hssf/usermodel/TestHSSFDateUtil.java
View File

@ -1,18 +1,18 @@
/* ==================================================================== /* ====================================================================
Copyright 2002-2004 Apache Software Foundation Copyright 2002-2004 Apache Software Foundation
Licensed under the Apache License, Version 2.0 (the "License"); Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License. you may not use this file except in compliance with the License.
You may obtain a copy of the License at You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0 http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS, distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and See the License for the specific language governing permissions and
limitations under the License. limitations under the License.
==================================================================== */ ==================================================================== */
@ -21,7 +21,9 @@ package org.apache.poi.hssf.usermodel;
import junit.framework.TestCase; import junit.framework.TestCase;
import java.util.Date; import java.util.Date;
import java.util.Calendar;
import java.util.GregorianCalendar; import java.util.GregorianCalendar;
import java.util.TimeZone;
/** /**
* Class TestHSSFDateUtil * Class TestHSSFDateUtil
@ -29,6 +31,7 @@ import java.util.GregorianCalendar;
* *
* @author * @author
* @author Dan Sherman (dsherman at isisph.com) * @author Dan Sherman (dsherman at isisph.com)
* @author Hack Kampbjorn (hak at 2mba.dk)
* @version %I%, %G% * @version %I%, %G%
*/ */
@ -78,4 +81,111 @@ public class TestHSSFDateUtil
dateIf1904.getTime(), dateIf1904.getTime(),
HSSFDateUtil.getJavaDate(excelDate,true).getTime()); HSSFDateUtil.getJavaDate(excelDate,true).getTime());
} }
/**
* Checks the conversion of a java.util.date to Excel on a day when
* Daylight Saving Time starts.
*/
public void testExcelConversionOnDSTStart() {
TimeZone cet = TimeZone.getTimeZone("Europe/Copenhagen");
TimeZone.setDefault(cet);
Calendar cal = new GregorianCalendar(2004, Calendar.MARCH, 28);
for (int hour = 0; hour < 24; hour++) {
// Skip 02:00 CET as that is the Daylight change time
// and Java converts it automatically to 03:00 CEST
if (hour == 2) {
continue;
}
cal.set(Calendar.HOUR_OF_DAY, hour);
Date javaDate = cal.getTime();
double excelDate = HSSFDateUtil.getExcelDate(javaDate);
double difference = excelDate - Math.floor(excelDate);
int differenceInHours = (int) (difference * 24 * 60 + 0.5) / 60;
assertEquals("Checking " + hour + " hour on Daylight Saving Time start date",
hour,
differenceInHours);
assertEquals("Checking " + hour + " hour on Daylight Saving Time start date",
javaDate.getTime(),
HSSFDateUtil.getJavaDate(excelDate).getTime());
}
}
/**
* Checks the conversion of an Excel date to a java.util.date on a day when
* Daylight Saving Time starts.
*/
public void testJavaConversionOnDSTStart() {
TimeZone cet = TimeZone.getTimeZone("Europe/Copenhagen");
TimeZone.setDefault(cet);
Calendar cal = new GregorianCalendar(2004, Calendar.MARCH, 28);
double excelDate = HSSFDateUtil.getExcelDate(cal.getTime());
double oneHour = 1.0 / 24;
double oneMinute = oneHour / 60;
for (int hour = 0; hour < 24; hour++, excelDate += oneHour) {
// Skip 02:00 CET as that is the Daylight change time
// and Java converts it automatically to 03:00 CEST
if (hour == 2) {
continue;
}
cal.set(Calendar.HOUR_OF_DAY, hour);
Date javaDate = HSSFDateUtil.getJavaDate(excelDate);
assertEquals("Checking " + hour + " hours on Daylight Saving Time start date",
excelDate,
HSSFDateUtil.getExcelDate(javaDate), oneMinute);
}
}
/**
* Checks the conversion of a java.util.Date to Excel on a day when
* Daylight Saving Time ends.
*/
public void testExcelConversionOnDSTEnd() {
TimeZone cet = TimeZone.getTimeZone("Europe/Copenhagen");
TimeZone.setDefault(cet);
Calendar cal = new GregorianCalendar(2004, Calendar.OCTOBER, 31);
for (int hour = 0; hour < 24; hour++) {
cal.set(Calendar.HOUR_OF_DAY, hour);
Date javaDate = cal.getTime();
double excelDate = HSSFDateUtil.getExcelDate(javaDate);
double difference = excelDate - Math.floor(excelDate);
int differenceInHours = (int) (difference * 24 * 60 + 0.5) / 60;
assertEquals("Checking " + hour + " hour on Daylight Saving Time end date",
hour,
differenceInHours);
assertEquals("Checking " + hour + " hour on Daylight Saving Time start date",
javaDate.getTime(),
HSSFDateUtil.getJavaDate(excelDate).getTime());
}
}
/**
* Checks the conversion of an Excel date to java.util.Date on a day when
* Daylight Saving Time ends.
*/
public void testJavaConversionOnDSTEnd() {
TimeZone cet = TimeZone.getTimeZone("Europe/Copenhagen");
TimeZone.setDefault(cet);
Calendar cal = new GregorianCalendar(2004, Calendar.OCTOBER, 31);
double excelDate = HSSFDateUtil.getExcelDate(cal.getTime());
double oneHour = 1.0 / 24;
double oneMinute = oneHour / 60;
for (int hour = 0; hour < 24; hour++, excelDate += oneHour) {
cal.set(Calendar.HOUR_OF_DAY, hour);
Date javaDate = HSSFDateUtil.getJavaDate(excelDate);
assertEquals("Checking " + hour + " hours on Daylight Saving Time start date",
excelDate,
HSSFDateUtil.getExcelDate(javaDate), oneMinute);
}
}
public static void main(String [] args) {
System.out
.println("Testing org.apache.poi.hssf.usermodel.TestHSSFDateUtil");
junit.textui.TestRunner.run(TestHSSFDateUtil.class);
}
} }