java获取日期之间天数的方法

//获取两个日期之间的天数
private int daysBetween(Date now, Date returnDate) {

  Calendar cNow = Calendar.getInstance();

  Calendar cReturnDate = Calendar.getInstance();

  cNow.setTime(now);

  cReturnDate.setTime(returnDate);

  setTimeToMidnight(cNow);

  setTimeToMidnight(cReturnDate);

  long todayMs = cNow.getTimeInMillis();

  long returnMs = cReturnDate.getTimeInMillis();

  long intervalMs = todayMs - returnMs;

  return millisecondsToDays(intervalMs);

}
//获取两个日期之间的分钟数

private int millisecondsToDays(long intervalMs) {

  return (int) (intervalMs / (1000 * 86400));

}
//获取两个日期之间的毫秒数

private void setTimeToMidnight(Calendar calendar) {

  calendar.set(Calendar.HOUR_OF_DAY, 0);

  calendar.set(Calendar.MINUTE, 0);

  calendar.set(Calendar.SECOND, 0);

}