Java 根据出生日期计算年龄

package com.edu.testAge;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

/**
 * @author June
 * @date 2021/12/27 16:05
 */
public class Client {
    public static Date parse(String strDate) throws ParseException {
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        return sdf.parse(strDate);
    }
    public static  int getAge(Date birthDay) throws Exception {
        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(
                    "日期填写错误！！");
        }
        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);
        int 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{
                age--;//当前月份在生日之前，年龄减一
            } } return age;
    }
    public static void main(String[] args) {
        try {
            int  age = getAge(parse("1984-09-27"));           //由出生日期获得年龄***
            System.out.println("age:"+age);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}