public static void main(String[] args) throws ParseException {
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
Date date1 = sdf.parse("2011-12-26");
Date date2 = sdf.parse("2011-06-08");
GregorianCalendar cal1 = new GregorianCalendar();
GregorianCalendar cal2 = new GregorianCalendar();
cal1.setTime(date1);
cal2.setTime(date2);
long gap = (cal2.getTimeInMillis()-cal1.getTimeInMillis())/(1000*3600*24);//从间隔毫秒变成间隔天数</strong>
System.out.println("相差"+gap+"天");
}