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