birthDate = idCard.substring(6,10)+"-"+idCard.substring(10,12)+"-"+idCard.substring(12,14)public static int getAgefromBirthTime(String birthTimeString){ // 先截取到字符串中的年、月、日 String strs[] = birthTimeString.trim().split("-"); int selectYear = Integer.parseInt(strs[0]); int selectMonth = Integer.parseInt(strs[1]); int selectDay = Integer.parseInt(strs[2]); // 得到當前時間的年、月、日 Calendar cal = Calendar.getInstance(); int yearNow = cal.get(Calendar.YEAR); int monthNow = cal.get(Calendar.MONTH) + 1; int dayNow = cal.get(Calendar.DATE); // 用當前年月日減去生日年月日 int yearMinus = yearNow - selectYear; int monthMinus = monthNow - selectMonth; int dayMinus = dayNow - selectDay; int age = yearMinus; if (yearMinus < 0) {// 選了未來的年份  age = 0; } else if (yearMinus == 0) {// 同年的，要么為1，要么為0  if (monthMinus < 0) {// 選了未來的月份   age = 0;  } else if (monthMinus == 0) {// 同月份的   if (dayMinus < 0) {// 選了未來的日期    age = 0;   } else if (dayMinus >= 0) {    age = 1;   }  } else if (monthMinus > 0) {   age = 1;  } } else if (yearMinus > 0) {  if (monthMinus < 0) {// 當前月>生日月  } else if (monthMinus == 0) {// 同月份的，再根據日期計算年齡   if (dayMinus < 0) {   } else if (dayMinus >= 0) {    age = age + 1;   }  } else if (monthMinus > 0) {   age = age + 1;  } } return age;}

public static int getAge(Date birthDay) throws Exception {   Calendar cal = Calendar.getInstance();   if (cal.before(birthDay)) {    throw new IllegalArgumentException(     "The birthDay is before Now.It's unbelievable!");   }   int yearNow = cal.get(Calendar.YEAR);   int monthNow = cal.get(Calendar.MONTH);   int dayOfMonthNow = cal.get(Calendar.DAY_OF_MONTH);   cal.setTime(birthDay);   int yearBirth = cal.get(Calendar.YEAR);   int monthBirth = cal.get(Calendar.MONTH);   int dayOfMonthBirth = cal.get(Calendar.DAY_OF_MONTH);   int age = yearNow - yearBirth;   if (monthNow <= monthBirth) {    if (monthNow == monthBirth) {     if (dayOfMonthNow < dayOfMonthBirth) age--;    }else{     age--;    }   }   System.out.println("age:"+age);   return age;  }