java~日期與字符串的轉化

SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");
sdf.parse(maxDate))//2018-01

val from =YearMonth.of(2018,1).toString(); //結果2018-01

 /**
   * from ~ to total months.
   *
   * @param minDate
   * @param maxDate
   * @return
   */
  private static List<String> getMonthBetween(String minDate, String maxDate) {
    ArrayList<String> result = new ArrayList<>();
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM");//格式化為年月

    Calendar min = Calendar.getInstance();
    Calendar max = Calendar.getInstance();
    try {
      min.setTime(sdf.parse(minDate));
      min.set(min.get(Calendar.YEAR), min.get(Calendar.MONTH), 1);

      max.setTime(sdf.parse(maxDate));
      max.set(max.get(Calendar.YEAR), max.get(Calendar.MONTH), 2);

    } catch (Exception ex) {
      System.out.println(ex.getMessage());
    }
    Calendar curr = min;
    while (curr.before(max)) {
      result.add(sdf.format(curr.getTime()));
      curr.add(Calendar.MONTH, 1);
    }

    return result;
  }