如何计算两个日期之间的天数

Question

我想计算两个日期之间的日期，但是某些情况下堆栈溢出的某些解决方案对我不起作用，例如：当结束日期比开始日期晚几天后开始

Answer 1

因此，通过此代码，我解决了所有问题，并且现在和以后都可以正常工作：）

private String getDifferenceBtwDates (String dateDebut, String dateFin){

    if (StringUtility.isEmptyOrNull(dateDebut) || StringUtility.isEmptyOrNull(dateFin)){
        return "0" ;
    }else {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");
        Date startDate = null;
        Date finDate = null;
        try {
            startDate = sdf.parse(dateDebut);
            finDate = sdf.parse(dateFin);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        Calendar calendar1 = Calendar.getInstance();
        Calendar calendar2 = Calendar.getInstance();
        calendar1.setTime(startDate);
        calendar2.setTime(finDate);

        /*
         * Use getTimeInMillis() method to get the Calendar's time value in
         * milliseconds. This method returns the current time as UTC
         * milliseconds from the epoch
         */
        long miliSecondForDate1 = calendar1.getTimeInMillis();
        long miliSecondForDate2 = calendar2.getTimeInMillis();
        // Calculate the difference in millisecond between two dates
        long diffInMilis = miliSecondForDate2 - miliSecondForDate1;
        /*
         * Now we have difference between two date in form of millsecond we can
         * easily convert it Minute / Hour / Days by dividing the difference
         * with appropriate value. 1 Second : 1000 milisecond 1 Hour : 60 * 1000
         * millisecond 1 Day : 24 * 60 * 1000 milisecond
         */
        long diffInDays = diffInMilis / (24 * 60 * 60 * 1000);
        return "" + diffInDays ;

    }
}