9

可能的重复:
计算两个 Java 日期实例之间的差异

如何在 Java 中获取两个日期之间的天数?

最好的方法是什么?这是我得到的,但不是最好的:

public static ConcurrentHashMap<String, String> getWorkingDaysMap(int year, 
    int month, int day){
        int totalworkingdays=0,noofdays=0;
        String nameofday = "";
        ConcurrentHashMap<String,String> workingDaysMap = 
            new ConcurrentHashMap<String,String>();
        Map<String,String> holyDayMap = new LinkedHashMap<String,String>();
        noofdays = findNoOfDays(year,month,day);

        for (int i = 1; i <= noofdays; i++) {
            Date date = (new GregorianCalendar(year,month - 1, i)).getTime();
            // year,month,day
            SimpleDateFormat f = new SimpleDateFormat("EEEE");
            nameofday = f.format(date);

            String daystr="";
            String monthstr="";

            if(i<10)daystr="0";
            if(month<10)monthstr="0";

            String formatedDate = daystr+i+"/"+monthstr+month+"/"+year;

            if(!(nameofday.equals("Saturday") || nameofday.equals("Sunday"))){
                workingDaysMap.put(formatedDate,formatedDate);
                totalworkingdays++;
            }
        }

        return workingDaysMap;
    }

public static int findNoOfDays(int year, int month, int day) {
        Calendar calendar = Calendar.getInstance();
        calendar.set(year, month - 1, day);
        int days = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
        return days;
    }
4

1 回答 1

22

我通常会这样做:

final long DAY_IN_MILLIS = 1000 * 60 * 60 * 24;

int diffInDays = (int) ((date1.getTime() - date2.getTime())/ DAY_IN_MILLIS );

不需要外部库,而且很简单


更新:刚刚看到你也想要“日期”,类似的方法适用:

//assume date1 < date2

List<Date> dateList = new LinkedList<Date>();
for (long t = date1.getTime(); t < date2.getTime() ; t += DAY_IN_MILLIS) {
  dateList.add(new Date(t));
}

当然,使用 JODA time 或其他 lib 可能会让您的生活更轻松,尽管我不认为当前的方式难以实现


更新:重要提示!这仅适用于没有夏令时或类似调整的时区,或者您对“天数差异”的定义实际上意味着“24 小时单位的差异”

于 2012-06-15T06:28:30.380 回答