java获取指定日期的前几天时间？

Calendar cal = Calendar.getInstance();

cal.set(2019,10,11);

Date time = cal.getTime();

System.out.println("当前指定日期是："+new SimpleDateFormat(fm).format(time));

cal.add(Calendar.DAY_OF_MONTH,-2);

cal.getTime();

System.out.println("前两天的日期是 "+new SimpleDateFormat(fm).format(cal.getTime()));