Java计算时间差

 /**
     * 计算两个时间差
     */
    public static String timeDistance(Date endDate, Date nowDate) {
        long nd = 1000 * 24 * 60 * 60L;
        long nh = 1000 * 60 * 60L;
        long nm = 1000 * 60L;
        // long ns = 1000;
        // 获得两个时间的毫秒时间差异
        long diff = endDate.getTime() - nowDate.getTime();
        // 计算差多少天
        long day = diff / nd;
        // 计算差多少小时
        long hour = diff % nd / nh;
        // 计算差多少分钟
        long min = diff % nd % nh / nm;
        // 计算差多少秒//输出结果
        // long sec = diff % nd % nh % nm / ns;
        return day + MessageUtils.message("Day") + hour + MessageUtils.message("Hour") + min + MessageUtils.message("Minutes");
    }

    /**
     * 计算两个时间差多少个小时
     * @param startTime
     * @param endTime
     * @return
     */
    public static int hourDistance(String startTime, String endTime) throws ParseException {
        String endDate = tToData(endTime);
        SimpleDateFormat SDF = new SimpleDateFormat(YYYY_MM_DD_HH_MM_SS);
        Date end = SDF.parse(endDate);
        Date start = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse(startTime);
        long beginTimestamp = start.getTime();
        long endTimestamp = end.getTime();
        long difference = endTimestamp - beginTimestamp;
        return (int) Math.ceil(difference / (1000 * 60 * 60));
    }