MyEclipse的注册码计算

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) {}}}