public static final int daysBetween(Date early, Date late) { 
     
         java.util.Calendar calst = java.util.Calendar.getInstance();   
         java.util.Calendar caled = java.util.Calendar.getInstance();   
         calst.setTime(early);   
          caled.setTime(late);   
          //設定時間為0時   
 

          calst.set(java.util.Calendar.HOUR_OF_DAY, 0);   
          calst.set(java.util.Calendar.MINUTE, 0);   
          calst.set(java.util.Calendar.SECOND, 0);   
          caled.set(java.util.Calendar.HOUR_OF_DAY, 0);   
          caled.set(java.util.Calendar.MINUTE, 0);   
          caled.set(java.util.Calendar.SECOND, 
 
0);   
         //得到兩個日期相差的天數   
          int days = ((int) (caled.getTime().getTime() / 1000) - (int) (calst   
                 .getTime().getTime() / 1000)) / 3600 / 24;   
          
         return days;   
    }   
   
    
    public static void main(String[] args)
    {
         Date earlydate = new Date();   
         Date latedate 
 
= new Date();   
         DateFormat df = DateFormat.getDateInstance();   
         try {   
             earlydate = df.parse("2009-09-21");   
             latedate = df.parse("2009-10-16");   
         } catch (ParseException e) {   
               e.printStackTrace();   
           }   
          int days = daysBetween(earlydate,latedate);   
          System.out.println(days);   
    }