通过出生日期获取年龄的方法--Java

项目中需要根据用户填写的出生日期获得用户的年龄，一般直接写成一个方法，然后调用方法进行计算比较省事。

下面介绍一种根据出生日期计算年龄的方法：

package com.hyhl.util;

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

public class AgeUtil {

     public static  Date parse(String strDate) throws ParseException {  
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");  
            return sdf.parse(strDate);  
        }  
       //由出生日期获得年龄  
        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;  
        }  
        
        public static void main(String args[]) { 
             try {
                int  age = getAge(parse("2991-10-21"));
                System.out.println("age=="+age);
            } catch (ParseException e) {
                e.printStackTrace();
            } catch (Exception e) {
                e.printStackTrace();
            } 
  
              
        }
}

直接方法即可

package com.hyhl.util;
import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;
public class AgeUtil {
public static  Date parse(String strDate) throws ParseException {          SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");          return sdf.parse(strDate);      }     //由出生日期获得年龄      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;      }          public static void main(String args[]) {      try {int  age = getAge(parse("2991-10-21"));System.out.println("age=="+age);} catch (ParseException e) {e.printStackTrace();} catch (Exception e) {e.printStackTrace();}             }}