两个日期类相减得到相差天数的小函数

public int daysBetween(Date smdate, Date bdate) throws Exception {SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");smdate = sdf.parse(sdf.format(smdate));bdate = sdf.parse(sdf.format(bdate));Calendar cal = Calendar.getInstance();cal.setTime(smdate);long time1 = cal.getTimeInMillis();cal.setTime(bdate);long time2 = cal.getTimeInMillis();long between_days = (time2 - time1) / (1000 * 3600 * 24);return Integer.parseInt(String.valueOf(between_days));}