1.首先引入jar包

 <dependency>
                <groupId>cn.hutool</groupId>
                <artifactId>hutool-all</artifactId>
                <version>5.3.7</version>
</dependency>

2.计算差值

	public static DateFormat getDateTimeFormat(){
		DateFormat dtf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		return dtf;
	}
//获取两个时间之前的差值(小时)
	public static String getSjScz(String rq1,String rq2)throws Exception{
		DateFormat simpleFormat = getDateTimeFormat();
		Date timeDate1 = simpleFormat.parse(rq1);
		Date timeDate2 = simpleFormat.parse(rq2);
		long hour=DateUtil.between(timeDate1, timeDate2, DateUnit.HOUR);
		return String.valueOf(hour);

	}
	//获取两个时间之前的差值(小时带小数)
	public static String getSjSch(String rq1,String rq2)throws Exception{
		DateFormat simpleFormat = getDateTimeFormat();
		Date timeDate1 = simpleFormat.parse(rq1);
		Date timeDate2 = simpleFormat.parse(rq2);
		long time1 = timeDate1.getTime();
		long time2 = timeDate2.getTime();
		double minutes = ((time1 - time2)*1.0 / (1000 * 60*60));
		return String.valueOf(minutes);
	}
	//获取两个时间之前的差值(分钟)
	public static String getSjScm(String rq1,String rq2)throws Exception{
		DateFormat simpleFormat = getDateTimeFormat();
		Date timeDate1 = simpleFormat.parse(rq1);
		Date timeDate2 = simpleFormat.parse(rq2);
		long minutes=DateUtil.between(timeDate1, timeDate2, DateUnit.MINUTE);
		return String.valueOf(minutes);

	}