java格式化以当前为准某偏移量的日期

    public String getDate(int Offset){
           Calendar theday = Calendar.getInstance();
           theday.add(Calendar.DAY_OF_MONTH, Offset);
           SimpleDateFormat formatter = new SimpleDateFormat("yyyyMMdd");
           String myday=formatter.format(theday.getTime());
           String strStart=myday.substring(0, 8);
           return strStart;
    }