您可以尝试较早版本的Java。

 public static String daysBetween(Date createdDate, Date expiryDate) {

        Calendar createdDateCal = Calendar.getInstance();
        createdDateCal.clear();
        createdDateCal.setTime(createdDate);

        Calendar expiryDateCal = Calendar.getInstance();
        expiryDateCal.clear();
        expiryDateCal.setTime(expiryDate);


        long daysBetween = 0;
        while (createdDateCal.before(expiryDateCal)) {
            createdDateCal.add(Calendar.DAY_OF_MONTH, 1);
            daysBetween++;
        }
        return daysBetween+"";
    }

因为您正在使用Scala，所以有一个非常好的Scala库Lamma。在南丫岛，你可以直接用-运算符减去日期

scala> Date(2015, 5, 5) - 2     // minus days by int
res1: io.lamma.Date = Date(2015,5,3)

scala> Date(2015, 5, 15) - Date(2015, 5, 8)   // minus two days => difference between two days
res2: Int = 7

这是另一个样本。基本上适用于用户定义的模式。

   public static LinkedHashMap<String, Object> checkDateDiff(DateTimeFormatter dtfObj, String startDate, String endDate)
   {
          Map<String, Object> dateDiffMap = new HashMap<String, Object>();
          DateTime start = DateTime.parse(startDate,dtfObj);
          DateTime end = DateTime.parse(endDate,dtfObj);
          Interval interval = new Interval(start, end);
          Period period = interval.toPeriod();

          dateDiffMap.put("ISO-8601_PERIOD_FORMAT", period);
          dateDiffMap.put("YEAR", period.getYears());
          dateDiffMap.put("MONTH", period.getMonths());
          dateDiffMap.put("WEEK", period.getWeeks());
          dateDiffMap.put("DAY", period.getWeeks());             
          dateDiffMap.put("HOUR", period.getHours());
          dateDiffMap.put("MINUTE", period.getMinutes());
          dateDiffMap.put("SECOND", period.getSeconds());

          return dateDiffMap;        
   }

另一个纯Java变体:

public boolean isWithin30Days(Calendar queryCalendar) {

    // 1. Take the date you are checking, and roll it back N days
    Calendar queryCalMinus30Days = Calendar.getInstance();
    queryCalMinus30Days.setTime(queryCalendar.getTime());
    queryCalMinus30Days.add(Calendar.DATE, -30); // subtract 30 days from the calendar

    // 2. Get respective milliseconds for the two Calendars: now & queryCal minus N days 
    long nowL = Calendar.getInstance().getTimeInMillis();
    long queryCalMinus30DaysL = queryCalMinus30Days.getTimeInMillis();

    // 3. if nowL is still less than the queryCalMinus30DaysL, it means queryCalendar is more than 30 days into future
    boolean isWithin30Days = nowL >= queryCalMinus30DaysL;

    return isWithin30Days;
}

感谢这里的入门代码:https://stackoverflow.com/a/30207726/2162226

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

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)。