看看Joda Time，它是一个改进的Java日期/时间API，应该可以很好地与Scala一起工作。

最好的办法是

(Date1-Date2)/86 400 000 

这个数字是一天的毫秒数。

一个日期和另一个日期的差异以毫秒为单位。

在双变量中收集答案。

public static String getDifferenceBtwTime(Date dateTime) {

    long timeDifferenceMilliseconds = new Date().getTime() - dateTime.getTime();
    long diffSeconds = timeDifferenceMilliseconds / 1000;
    long diffMinutes = timeDifferenceMilliseconds / (60 * 1000);
    long diffHours = timeDifferenceMilliseconds / (60 * 60 * 1000);
    long diffDays = timeDifferenceMilliseconds / (60 * 60 * 1000 * 24);
    long diffWeeks = timeDifferenceMilliseconds / (60 * 60 * 1000 * 24 * 7);
    long diffMonths = (long) (timeDifferenceMilliseconds / (60 * 60 * 1000 * 24 * 30.41666666));
    long diffYears = (long)(timeDifferenceMilliseconds / (1000 * 60 * 60 * 24 * 365));

    if (diffSeconds < 1) {
        return "one sec ago";
    } else if (diffMinutes < 1) {
        return diffSeconds + " seconds ago";
    } else if (diffHours < 1) {
        return diffMinutes + " minutes ago";
    } else if (diffDays < 1) {
        return diffHours + " hours ago";
    } else if (diffWeeks < 1) {
        return diffDays + " days ago";
    } else if (diffMonths < 1) {
        return diffWeeks + " weeks ago";
    } else if (diffYears < 12) {
        return diffMonths + " months ago";
    } else {
        return diffYears + " years ago";
    }
}   

public static void main(String[] args) {

    String dateStart = "01/14/2012 09:29:58";
    String dateStop = "01/14/2012 10:31:48";

    SimpleDateFormat format = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");

    Date d1 = null;
    Date d2 = null;

    try {
        d1 = format.parse(dateStart);
        d2 = format.parse(dateStop);

        DateTime date11 = new DateTime(d1);
        DateTime date22 = new DateTime(d2);
        int days = Days.daysBetween(date11.withTimeAtStartOfDay(), date22.withTimeAtStartOfDay()).getDays();
        int hours = Hours.hoursBetween(date11, date22).getHours() % 24;
        int minutes = Minutes.minutesBetween(date11, date22).getMinutes() % 60;
        int seconds = Seconds.secondsBetween(date11, date22).getSeconds() % 60;
        if (hours > 0 || minutes > 0 || seconds > 0) {
            days = days + 1;
        }

        System.out.println(days);

    } catch (Exception e) {
        e.printStackTrace();
    }

}

这将为同一天提供日期差异

int daysDiff = (date1.getTime() - date2.getTime()) / MILLIS_PER_DAY;

一个稍微简单一点的选择:

System.currentTimeMillis() - oldDate.getTime()

至于“更好”，你到底需要什么?将时间持续时间表示为小时数和天数等的问题是，由于日期的复杂性，它可能导致不准确和错误的期望(例如，由于夏令时，一天可能有23或25小时)。