Java Data Type - 如何在Java 8中的YearMonth中创建固定的日期，如信用卡到期日

import java.time.Month;
import java.time.YearMonth;

public class Main {
  public static void main(String[] argv) {
    YearMonth currentYearMonth = YearMonth.now();
    System.out.printf("Days in month year %s: No of days: %s \n",
        currentYearMonth, currentYearMonth.lengthOfMonth());
    YearMonth creditCardExpiry = YearMonth.of(2018, Month.FEBRUARY);
    System.out.printf("Your credit card expires on %s: No of days: %s \n",
        creditCardExpiry, creditCardExpiry.lengthOfMonth());

  }
}