Android-计算两个日期之间间隔的天数

System.out.print("开始时间:");

            String str1 = beginTime; // "yyyyMMdd"格式 如 20131022
            System.out.println("\n结束时间:");
            String str2 = _endTime; // "yyyyMMdd"格式 如 20131022
            SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyyMMdd");// 输入日期的格式
            Date date1 = null;
            try {
                date1 = simpleDateFormat.parse(str1);
            } catch (ParseException e) {
                e.printStackTrace();
            }
            Date date2 = null;
            try {
                date2 = simpleDateFormat.parse(str2);
            } catch (ParseException e) {
                e.printStackTrace();
            }
            GregorianCalendar cal1 = new GregorianCalendar();
            GregorianCalendar cal2 = new GregorianCalendar();
            cal1.setTime(date1);
            cal2.setTime(date2);
            double dayCount = (cal2.getTimeInMillis() - cal1.getTimeInMillis()) / (1000 * 3600 * 24);// 从间隔毫秒变成间隔天数
            System.out.println("\n相差" + dayCount + "天");