Java 通过身份证获取生日、性别、年龄

package com.taiping.ecms.car.utils;

import java.util.Calendar;
import java.util.Date;

/**
 * 字符串相关工具类
 * @author Alex
 *
 */
public class StringUtils {
    
    /**
     * 格式化字符串第一个字符为大写
     * @param field
     * @return
     */
    public static String upperFirstString(String field){
        if(field.length() <= 0 || field == null){
            return field;
        }
        String firstLetter = field.substring(0, 1).toUpperCase();    
        String formatString = firstLetter + field.substring(1); 
        
        
        return formatString;
    }
    
    /**
     * 功能:在判定已经是正确的身份证号码之后,查找出此人性别
     * @param idCard-身份证号码
     * @return 1-男或者 2-女
     */
    public static String getSex(String idCard) {
        String sex = "";
        if (idCard.length() == 15) {
            sex = idCard.substring(idCard.length() - 3, idCard.length());
        } else {
            sex = idCard.substring(idCard.length() - 4, idCard.length() - 1);
        }
        int sexNum = Integer.parseInt(sex) % 2;
        if (sexNum == 0) {
            return "2";
        }
        return "1";
    } 
    /**
     * 根据出生日期获取年龄
     * @param birthDay
     * @return
     * @throws Exception
     */
    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--; 
            } 
        } 
        return age; 
    }
    /**
     * 功能:在判定已经是正确的身份证号码之后,查找出此人出生日期
     * @param idCard-身份证号码
     * @return 出生日期 XXXX MM-DD
     */  
    public static String getBirthday(String idCard) {
        String Ain = "";
        if (idCard.length() == 18) {
            Ain = idCard.substring(0, 17);
        } else if (idCard.length() == 15) {
            Ain = idCard.substring(0, 6) + "19" + idCard.substring(6, 15);
        }
        String strYear = Ain.substring(6, 10);// 年份
        String strMonth = Ain.substring(10, 12);// 月份
        String strDay = Ain.substring(12, 14);// 日期
        return strYear + "-" + strMonth + "-" + strDay;
    } 
    
    
}