我正在解决将GregorianCalendar转换为java.util.Date对象的问题,该GregorianCalendar仅代表当前日期(即,// 2013-03-10 00:00:00)。该测试背后的想法是获取两个日期-一个仅包含当前日期的日期,以及一个仅包含当前时间的日期(即1970-01-01 12:30:45),并将它们合并为一个表示日期的日期和时间(2013-03-10 12:30:45)。
在DST切换发生的那天,测试失败-因为将GregorianCalendar转换为日期对象(Date date = dateCal.getTime();在下面的代码中)损失了一个小时,因此回滚到(2013-03-09 23:00:00)。我该如何避免这种情况发生?
public static Date addTimeToDate(Date date, Date time) {
if (date == null) {
throw new IllegalArgumentException("date cannot be null");
} else if (time == null) {
throw new IllegalArgumentException("time cannot be null");
} else {
Calendar timeCal = GregorianCalendar.getInstance();
timeCal.setTime(time);
long timeMs = timeCal.getTimeInMillis() + timeCal.get(Calendar.ZONE_OFFSET) + timeCal.get(Calendar.DST_OFFSET);
return addMillisecondsToDate(date, timeMs);
}
}
@Test
public void testAddTimeToDate() {
Calendar expectedCal = Calendar.getInstance();
Calendar dateCal = Calendar.getInstance();
dateCal.clear();
dateCal.set(expectedCal.get(Calendar.YEAR), expectedCal.get(Calendar.MONTH), expectedCal.get(Calendar.DAY_OF_MONTH));
Calendar timeCal = Calendar.getInstance();
timeCal.clear();
timeCal.set(Calendar.HOUR_OF_DAY, expectedCal.get(Calendar.HOUR_OF_DAY));
timeCal.set(Calendar.MINUTE, expectedCal.get(Calendar.MINUTE));
timeCal.set(Calendar.SECOND, expectedCal.get(Calendar.SECOND));
timeCal.set(Calendar.MILLISECOND, expectedCal.get(Calendar.MILLISECOND));
Date expectedDate = expectedCal.getTime();
Date date = dateCal.getTime();
Date time = timeCal.getTime();
Date actualDate = DateUtil.addTimeToDate(date, time);
assertEquals(expectedDate, actualDate);
}
最佳答案
为什么在计算中包括时区偏移量?当您在Java中使用毫秒时,它们始终以UTC为单位。您无需进行任何其他转换。
您最大的问题可能是尝试手动进行这些日期/时间计算。您应该使用Calendar类本身来处理计算。