Java准确计算Date相差天数

https://blog.csdn.net/qq_35890572/article/details/96427499

    public static int getDayDiffer(Date startDate, Date endDate) throws ParseException {
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
        long startDateTime = dateFormat.parse(dateFormat.format(startDate)).getTime();
        long endDateTime = dateFormat.parse(dateFormat.format(endDate)).getTime();
        return (int) ((endDateTime - startDateTime) / (1000 * 3600 * 24));
    }

 获取当天时间的开始时间戳

https://blog.csdn.net/qq_31519989/article/details/88420044

Java获取当前时间戳/时间戳转换