//计算两日期相隔的天数
//first="20080501";
//second="20080515";
    public int nDaysBetweenTwoDate(String first, String second) {
        SimpleDateFormat df = new SimpleDateFormat("yyyyMMdd");
        Date firstDate = null;
        Date secondDate = null;
        int nDay = 0;
        try {
            firstDate = df.parse(first);
            secondDate = df.parse(second);
            nDay = (int) ((secondDate.getTime() - firstDate.getTime()) / (24 * 60 * 60 * 1000));
        } catch (Exception e) {
            e.printStackTrace();
        }
        return nDay;
    }