Java 计算两个日期之间相差小时数

 private static  BigDecimal getDifferHour(String startDateTime, String endDateTime) throws ParseException {
        SimpleDateFormat dateFormat=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date parse1 = dateFormat.parse(startDateTime);
        Date parse2 = dateFormat.parse(endDateTime);
        long mills=parse2.getTime()-parse1.getTime();
		//转 BigDecimal
        BigDecimal fz=new BigDecimal(mills);
		//转 BigDecimal
        BigDecimal fm=new BigDecimal(60*60*1000);
        BigDecimal bwtHours=fz.divide(fm,2,BigDecimal.ROUND_HALF_UP);
        return bwtHours;
    }