身份证的校验

package lianxi;

import java.io.*;
import java.lang.*;

class CardID{ 
  public static void main(String []args) throws IOException{
  
     System.out.println("请输入一个身份证号码：");
    
     BufferedReader s= new BufferedReader(new InputStreamReader(System.in));
     String ww=s.readLine();
   
     if(ww.length()==15){
         System.out.println("该居民身份证是旧的身份证！");
         getInfof(ww);
         Convert(ww);
     }
    else if(ww.length()==18){
         System.out.println("该居民身份证是新的身份证！");
         getInfoe(ww);
     }
    else{
          System.out.println("该居民身份证号码位数不符！");
     }
  }
  public static void getInfof(String s){
   
       String M=new String(s);
      
       int y=Integer.parseInt(M.substring(6,8));
       int m=Integer.parseInt(M.substring(8,10));
       int d=Integer.parseInt(M.substring(10,12));
      
       if (m<1 || m>12 || d<1 || d>31 || ((m==4 || m==6 || m==9 || m==11) && d>30) ||(m==2 && (((y+1900) % 4>0 && d>28) || d>29))){
       
        System.out.println("該居民身份證出生年月日错误!");
      }
        else{
         
            System.out.println("该居民出生地："+M.substring(0,6));
            System.out.println("该居民出生时间为："+y+"年"+m+"月"+d+"日");
         }
           
         int sex=Integer.parseInt(M.substring(14,15));
           
        if(sex%2==0){
        System.out.println("该居民为：女性");}
         else{
        System.out.println("该居民为：男性");
         }
    }
   public static void getInfoe(String s){
   
       String M=new String(s);
      
       int y=Integer.parseInt(M.substring(6,10));
       int m=Integer.parseInt(M.substring(10,12));
       int d=Integer.parseInt(M.substring(12,14));
      
       int[] xx={2,4,8, 5,10,9,7, 3,6,1,2, 4,8,5,10, 9,7};
       char[] yy={'1','0','X','9','8','7','6','5','4','3','2'};
      
       int mm=0;
      
       int[] gg = new int[18];