java计算两个日期之间相差的天数

java计算两个日期之间相差的天数

/**
 * 计算两个日期之间相差的天数
 * @param smdateStr 较小的时间
 * @param bdate  较大的时间
 * @return 相差天数
 */
public static int daysBetween(String smdateStr,Date bdate){
	try {
		SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
		Date smdate = sdf.parse(smdateStr);
		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 betweenDays=(time2-time1)/(1000*3600*24);
		return Integer.parseInt(String.valueOf(betweenDays));
	} catch (Exception e) {
		e.printStackTrace();
	}
   return -1;
}