写加密方法，希望大神知点和分享我们的技术

/**

* 将接收到的site_guide_id进行转码到页面显示

* @param num site_guide_id

* @return 转码后的字符串

*/

public static String encodeShowId(Long num){

System.out.println(" 加密的 === num : "+num);

int a = 510;

int b = 3;

String letter[] = { "A", "B", "C", "D", "E", "F", "G", "H", "I", "G"};

//随便进行运算后再将后两位远的成字母显示

int newnum= num.intValue()*a/b;

String pass = newnum + (letter[newnum%100/10])+ (letter[newnum%10]);

return pass;

}

/**

* 将页面显示的转码后的GUIDE_ID反编码

* @param pass

* @return

*/

public static int decodeShowId(String pass){

int a = 510;

int b = 3;

//去掉后两位再按原规则反向运算

String left = pass.substring(0,pass.length()-2);

int num = Integer.parseInt(left);

num = num*b/a;

return num;

}