/**
 * 根据生日计算年龄
 * @param birthDay
 * @return
 */
public static String getAgeByBirth(Date birthDay) {
    StringBuffer sb = new StringBuffer();
    try {
        int age = 0;
        int month = 0;
        Calendar cal = Calendar.getInstance();
        if (cal.before(birthDay)) { //出生日期晚于当前时间，无法计算
            throw new IllegalArgumentException(
                    "The birthDay is before Now.It's unbelievable!");
        }
        int yearNow = cal.get(Calendar.YEAR);  //当前年份
        int monthNow = cal.get(Calendar.MONTH);  //当前月份
        int dayOfMonthNow = cal.get(Calendar.DAY_OF_MONTH); //当前日期
        cal.setTime(birthDay);
        int yearBirth = cal.get(Calendar.YEAR);
        int monthBirth = cal.get(Calendar.MONTH);
        int dayOfMonthBirth = cal.get(Calendar.DAY_OF_MONTH);
        age = yearNow - yearBirth;   //计算整岁数
        if (monthNow <= monthBirth) {
            if (monthNow == monthBirth) {
                //if (dayOfMonthNow < dayOfMonthBirth) age--;//当前日期在生日之前，年龄减一
            } else {
                month = monthNow - monthBirth + 12;
                age--;//当前月份在生日之前，年龄减一
            }
        } else {
            month = monthNow - monthBirth;
        }

        if (age < 4) {
            if (age == 0) {
                sb.append(month + "个月");
            } else if (month == 0) {
                sb.append(age + "岁");
            } else {
                sb.append(age + "岁" + month + "个月");
            }
        } else {
            sb.append(age + "岁");
        }
    } catch (Exception e) {
        return "";
    }
    return sb.toString();
}