我希望通过使用格里高利历来减去java中的日期来获得天数差异：

Question

GregorianCalendar last = new GregorianCalendar(py,pm-1,pd);
System.out.println(last.getTime());
GregorianCalendar present = new GregorianCalendar(py,pm-1,pd);
System.out.println(present.getTime());

long diff = Math.abs(prsent.getTime() - last.getTime());

减去这两个日期时遇到的问题

Answer 1

ChronoUnit可以用于日期之间的区别：

long minutesDiff = ChronoUnit.MINUTES.between(present.toInstant(), last.toInstant());