日期相减得到天数

SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
Calendar calendar = Calendar.getInstance();
calendar.set(2013, 10, 6);
long start = calendar.getTimeInMillis();
Date startDate = new Date(start);
System.out.println(startDate);
calendar.set(2013, 10, 10);
long end = calendar.getTimeInMillis();
Date endDate = new Date(end);

long dateResult = endDate.getTime() - startDate.getTime();
int day = (int) (dateResult/24L/60L/60L/1000L);
System.out.println(day);