myeclipse7.0注册码算法

package com.edj.sessionbean;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class MyeclipseGen {
private static final String LL = "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 String getSerial(String userId, String licenseNum) {
 java.util.Calendar cal = java.util.Calendar.getInstance();
 cal.add(1, 3);
 cal.add(6, -1);
 java.text.NumberFormat nf = new java.text.DecimalFormat("000");
 licenseNum = nf.format(Integer.valueOf(licenseNum));
 String verTime = new StringBuilder("-").append(
 new java.text.SimpleDateFormat("yyMMdd").format(cal.getTime()))
 .append("0").toString();
 String type = "YE3MP-";
 String need = new StringBuilder(userId.substring(0, 1)).append(type)
 .append("300").append(licenseNum).append(verTime).toString();
 String dx = new StringBuilder(need).append(LL).append(userId)
 .toString();
 int suf = this.decode(dx);
 String code = new StringBuilder(need).append(String.valueOf(suf))
 .toString();
 return this.change(code);
}

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

private String change(String s) {
 byte[] abyte0;
 char[] ac;
 int i;
 int k;
 int j;
 abyte0 = s.getBytes();
 ac = new char[s.length()];
 i = 0;
 k = abyte0.length;
 while (i < k) {
 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;
 i++;
 }
 return String.valueOf(ac);
}

public MyeclipseGen() {
 super();
}

public static void main(String[] args) {
 try {
 System.out.println("please input register name:");
 BufferedReader reader = new BufferedReader(new InputStreamReader(
 System.in));
 String userId = null;
 userId = reader.readLine();
 MyeclipseGen myeclipsegen = new MyeclipseGen();
 String res = myeclipsegen.getSerial(userId, "5");
 System.out.println("Serial:" + res);
 reader.readLine();
 } catch (IOException ex) {
 }
}
}