java注册机

public class Main {
private static final String L = "Decompiling this copyrighted software is a violation of both your license agreement and the Digital Millenium Copyright Act of 1998 (http://www.loc.gov/copyright/legislation/dmca.pdf). Under section 1204 of the DMCA, penalties range up to a $500,000 fine or up to five years imprisonment for a first offense. Think about it; pay for a license, avoid prosecution, and feel better about yourself.";

public static void main(String[] args) {
   String userId = "xiangfei";
   // MyEclipse4.1 GA
   // 其中491(4.9.1)/400(4.0)/401(4.1)/501(5.1.0)，()内为版本号，9912310代表注册码过期时间2099/12/31
   String need = userId.substring(0, 1) + "YE3MP-401-00-9912310";
   // MyEclipse4.0.0 GA
   // String need = userId.substring(0,1) + "YE3MP-400-01-9912310";
   // MyEclipse4.9.1
   // String need = userId.substring(0,1) + "YE3MP-491-01-9912310";
   // MyEclipse5.1.0 GA
   // String need = userId.substring(0,1) + "YE3MP-501-00-9912310";
   String dx = need + L + userId;
   int suf = decode(dx);
   // System.out.println("SUF:"+suf);
   String code = need + suf;
   System.out.println(change(code));
}

static int decode(String s) {
   int i = 0;
   char ac[] = s.toCharArray();
   int j = 0;
   for (int k = ac.length; j < k; j++) {
     i = 31 * i + ac[j];
   }
   return Math.abs(i);
}

static String change(String s) {
   byte abyte0[] = s.getBytes();
   char ac[] = new char[s.length()];
   int i = 0;
   for (int k = abyte0.length; i < k; i++) {
     int j = abyte0[i];
     if (j >= 48 && j <= 57)
       j = ((j - 48) + 5) % 10 + 48;
     else if (j >= 65 && j <= 90)
       j = ((j - 65) + 13) % 26 + 65;
     else if (j >= 97 && j <= 122)
       j = ((j - 97) + 13) % 26 + 97;
     ac[i] = (char) j;
   }
   return String.valueOf(ac);
}
}