java计算年龄

public static int getAgeByCardId(String card) throws Exception {
Integer len = card.length();
if (len == CHINA_ID_MIN_LENGTH) {
card = conver15CardTo18(card);
}
String birthDate = card.substring(6, 14);
SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
Date date = sdf.parse(birthDate);
return calcAge(date);
} /**
* 由出生日期获得年龄 精确到天
* @param birthDay
* @return
* @throws Exception
*/
public static int calcAge(Date birthDay) throws Exception {
Calendar cal = Calendar.getInstance();
if (cal.before(birthDay)) {
throw new IllegalArgumentException("出生日期不能晚于当前日期");
}
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--;
}
}
return age;
}

/**
* 根据身份编号获取年龄
*
* @param idCard
* 身份编号
* @return 年龄
*/
public static int getAgeByIdCard(String idCard) {
int iAge = 0;
if (idCard.length() == CHINA_ID_MIN_LENGTH) {
idCard = conver15CardTo18(idCard);
}
String year = idCard.substring(6, 10);
Calendar cal = Calendar.getInstance();
int iCurrYear = cal.get(Calendar.YEAR);
iAge = iCurrYear - Integer.valueOf(year);
return iAge;
}