java for循环 if else JAVA for循环加入时间间隔

public static void main(String[] args) {
  //起始时间
  String str="20170805"; 
  //结束时间
  String str1="20170810";

  SimpleDateFormat format=new   SimpleDateFormat("yyyyMMdd");
  Calendar start = Calendar.getInstance();
  Calendar end = Calendar.getInstance();
  try {
    start.setTime(format.parse(str));
    end.setTime(format.parse(str1));
  } catch (java.text.ParseException e) {
    e.printStackTrace();
  }
  while(start.before(end))
  {
      System.out.println(format.format(start.getTime()));
      start.add(Calendar.DAY_OF_MONTH,1);
  }
}

结果：
20170805
20170806
20170807
20170808
20170809
20170810