java中时间问题,高分请教!!

Question

写的比较烦，仅作参考
          GregorianCalendar d=new GregorianCalendar();
          d.set(Calendar.YEAR,2005);
          d.set(Calendar.MONTH,9);
          d.set(Calendar.DAY_OF_MONTH,1);
          Date dd=d.getTime();
          System.out.println(dd);
          d.add(Calendar.MONTH,1);
           Date dd2=d.getTime();
          System.out.println(dd2);
          System.out.println((dd2.getTime()-dd.getTime())/(1000*60*60*24));