获取两个日期之间相差的天数

/**
     * 计算两个日期之间相差的天数.
     * @param startDate  开始日期
     * @param endDate    结束日期
     * @return 天数
     */
    public int daysBetween(Date startDate, Date endDate) {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        try {
            endDate = sdf.parse(sdf.format(endDate));
            startDate = sdf.parse(sdf.format(startDate));
        } catch (Exception e) {
            log.error("日期转换异常：", e);
        }
        Calendar cal = Calendar.getInstance();
        cal.setTime(endDate);
        long time1 = cal.getTimeInMillis();
        cal.setTime(startDate);
        long time2 = cal.getTimeInMillis();
        long between_days = (time2 - time1) / (1000 * 3600 * 24);
        return Math.abs(Integer.parseInt(String.valueOf(between_days)));
    }