java 时间间隔天数

public static Long getDaysBetween(long startDate, long endDate) {
Calendar fromCalendar = Calendar.getInstance();
fromCalendar.setTimeInMillis(startDate);
fromCalendar.set(Calendar.HOUR_OF_DAY, 0);
fromCalendar.set(Calendar.MINUTE, 0);
fromCalendar.set(Calendar.SECOND, 0);
fromCalendar.set(Calendar.MILLISECOND, 0);

Calendar toCalendar = Calendar.getInstance();
toCalendar.setTimeInMillis(endDate);
toCalendar.set(Calendar.HOUR_OF_DAY, 0);
toCalendar.set(Calendar.MINUTE, 0);
toCalendar.set(Calendar.SECOND, 0);
toCalendar.set(Calendar.MILLISECOND, 0);

return (toCalendar.getTime().getTime() - fromCalendar.getTime().getTime()) / (1000 * 60 * 60 * 24);
}