code: private static boolean checkBirthday(String idNumberBirthdayStr) {
          Integer year = null;
          try {
              year = Integer.valueOf(idNumberBirthdayStr.substring(0, 4));
          } catch (Exception e) {
          }
          if (null == year) {
              return false;
          }
          if (isLeapYear(year)) {
          	return regexBirthdayInLeapYear.matcher(idNumberBirthdayStr).matches();
          } else {
              return regexBirthdayInCommonYear.matcher(idNumberBirthdayStr).matches();
          }
      }
docs: 身份证出生日期嘛检查