java 计算两个date日期相差天数或者时间差

相差天数计算：

    /**
     * 相差天数计算
     */
    public int differentDaysByMillisecond(Date date1, Date date2) {
        return Math.abs((int) ((date2.getTime() - date1.getTime()) / (1000 * 3600 * 24)));
    }

两个时间差计算：

    /**
     * 两个时间差计算
     */
    public String getDatePoor(Date endDate, Date nowDate) {
        long nd = 1000 * 24 * 60 * 60;
        long nh = 1000 * 60 * 60;
        long nm = 1000 * 60;
        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 + "天" + hour + "小时" + min + "分钟" + sec + "秒";
    }