public static int differentDays(Date date1,Date date2) {
Calendar cal1 = Calendar.getInstance();
cal1.setTime(date1);
Calendar cal2 = Calendar.getInstance();
cal2.setTime(date2);
int day1= cal1.get(Calendar.DAY_OF_YEAR);
int day2 = cal2.get(Calendar.DAY_OF_YEAR);
int year1 = cal1.get(Calendar.YEAR);
int year2 = cal2.get(Calendar.YEAR);
if(year1 != year2) //同一年
{
int timeDistance = 0 ;
for(int i = year1 ; i < year2 ; i ++)
{
if(i%4==0 && i%100!=0 || i%400==0) //閏年
{
timeDistance += 366;
}
else //不是閏年
{
timeDistance += 365;
}
}
return timeDistance + (day2-day1) ;
}
else //不同年
{
System.out.println("判斷day2 - day1 : " + (day2-day1));
return day2-day1;
}
}
public static int differentDaysByMillisecond(Date date1,Date date2)
{
int days = (int) ((date2.getTime() - date1.getTime()) / (1000*3600*24));
return days;
}
java.time.LocalDate
LocalDate end = LocalDate.parse("2022-04-20", DateTimeFormatter.ofPattern("yyyy-MM-dd"));
LocalDate begin = LocalDate.of(end.getYear(), 1, 1);
int days = end.toEpochDay() - begin.toEpochDay() + 1;
