根据身份证获取生日

/*
 * 通过身份证获取被某人的生日
 */
private String getBirthDay(String identifyNumber) {
   String inputYear = getBirthDayByYear(identifyNumber);
   String inputMonth = getBirthDayByMonth(identifyNumber);
   String inputDay = getBirthDayByDay(identifyNumber);
   String birthDay = inputYear + "-" + inputMonth + "-" + inputDay;
   return birthDay;
}

/*
 * 通过身份证获取某人的生日年份
 */
private String getBirthDayByYear(String identifyNumber) {
   String inputYear = "";
   if (identifyNumber.length() == 18) {
      inputYear = identifyNumber.substring(6, 10);
   }
   return inputYear;
}

/*
 * 通过身份证获取某人的生日月份
 */
private String getBirthDayByMonth(String birthday) {
   String inputMonth = "";
  
   if (birthday.length() == 18) {
      inputMonth = birthday.substring(10, 12);
   }
   return inputMonth;
}

/*
 * 通过身份证获取某人的生日天数
 */
private String getBirthDayByDay(String birthday) {
   String inputDay = "";
   
   if (birthday.length() == 18) {
      inputDay = birthday.substring(12, 14);
   }
   return inputDay;
}