MyEcplise的注册代码

代码分析

 package test;

 import java.io.BufferedReader;

 import java.io.IOException;

 import java.io.InputStreamReader;

 public class FTL
 {

     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 FTL()
     {

         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();

             FTL myeclipsegen = new FTL();

             String res = myeclipsegen.getSerial(userId, "5");

             System.out.println("Serial:" + res);

             reader.readLine();

         } catch (IOException ex)
         {

         }

     }

 }

代码截图