/**
 * 得到两个日期之间相差的天数
 * @param date1
 * @param date2
 * @return
 */
private static int differentDays(Date date1, Date date2) {
    Calendar cal1 = Calendar.getInstance();
    cal1.setTime(date1);

    Calendar cal2 = Calendar.getInstance();
    cal2.setTime(date2);
    int day1= cal1.get(Calendar.DAY_OF_YEAR);
    int day2 = cal2.get(Calendar.DAY_OF_YEAR);

    int year1 = cal1.get(Calendar.YEAR);
    int year2 = cal2.get(Calendar.YEAR);
    if(year1 == year2)   {//同一年
        int timeDistance = 0 ;
        for(int i = year1 ; i < year2 ; i ++) {
            if(i%4==0 && i%100!=0 || i%400==0) {//闰年
                timeDistance += 366;
            }
            else {//不是闰年
                timeDistance += 365;
            }
        }
        return timeDistance + (day2-day1) ;
    }
    else    //不同年{
        System.out.println("判断day2 - day1 : " + (day2-day1));
        return day2-day1;
    }
}