自己生成myeclipse注册码的代码

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) {  
   }  
}  
}