Java Calendar 计算时间差

public static void main(String[] args) {
		Calendar c=Calendar.getInstance();
		int y=2016;//年
		int M=1;//月
		int d=1;//日
		int H=0;//时
		int m=0;//分
		int s=0;//秒
		c.set(Calendar.YEAR, y);
		c.set(Calendar.MONTH, M-1);
		c.set(Calendar.DATE, d);
		c.set(Calendar.HOUR_OF_DAY, H);
		c.set(Calendar.MINUTE, m);
		c.set(Calendar.SECOND, s);
		Calendar now=Calendar.getInstance();
		long aTime=now.getTimeInMillis();
		long bTime=c.getTimeInMillis();
		long cTime=aTime-bTime;
		long sTime=cTime/1000;//时间差，单位：秒
		long mTime=sTime/60;
		long hTime=mTime/60;
		long dTime=hTime/24;
		SimpleDateFormat f=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		System.out.println("当前时间："+f.format(now.getTime()));
		System.out.println("设定时间："+f.format(c.getTime()));
		System.out.println("时间差："+dTime+"天"+hTime%24+"时"+mTime%60+"分"+sTime%60+"秒");
	}