java中两个16进制字符串异或

java中，两个16进制的字符串异或，经常用于加密机加解密当中 ，具体异或的方法如下：
package com.foxconn; 
import java.text.ParseException; 
 
 
public class Aa { 
    private static String hexStr = "0123456789ABCDEF";  
    public static void main(String args[]) throws ParseException{ 
         
       String code1 = encode("9CE00K00781065"); 
           String code2 = encode("TOX$123FTOX$321"); 
       System.out.println(code1); 
       System.out.println(code2); 
       System.out.println("7F0C1D14017903767F6814010203"); 
        
        String result =""; 
       for(int i=0; i<code1.length();i++){ 
           char c1 = code1.charAt(i); 
           char c2 = code2.charAt(i); 
           String a = convertHexToBinary(c1+""); 
           String b = convertHexToBinary(c2+""); 
           byte [] aa = a.getBytes(); 
           byte [] bb = b.getBytes(); 
           String cc =""; 
           for( int j = 0;j<aa.length;j++ ){ 
              cc +=   aa[j]^bb[j];    
           } 
           String tmp =Integer.toHexString(Integer.valueOf(cc,2).intValue()).toString(); 
           
          result +=tmp; 
       } 
    } 
     
    public static String convertHexToBinary(String hexString){ 
        long l = Long.parseLong(hexString, 16); 
        String binaryString = Long.toBinaryString(l); 
        int shouldBinaryLen = hexString.length()*4; 
        StringBuffer addZero = new StringBuffer(); 
        int addZeroNum = shouldBinaryLen-binaryString.length(); 
        for(int i=1;i<=addZeroNum;i++){ 
            addZero.append("0"); 
        } 
        return addZero.toString()+binaryString;         
    } 
     
    public static String encode(String str) { 
           // 根据默认编码获取字节数组 
           byte[] bytes = str.getBytes(); 
           String strs = ""; 
           // 将字节数组中每个字节拆解成2位16进制整数 
           for (int i = 0; i < bytes.length; i++) { 
                  //取得高四位 
            strs += hexStr.charAt((bytes[i] & 0xf0) >> 4); 
           // System.out.println(i+"--"+bytes[i]+"----"+(bytes[i] & 0xf0)+"----"+hexString.charAt((bytes[i] & 0xf0) >> 4)+"---"+hexString.charAt((bytes[i] & 0x0f) >> 0)); 
            //取得低四位 
            strs += hexStr.charAt((bytes[i] & 0x0f) >> 0); 
           } 
           return strs; 
        } 
}