MyEclipse 注册机

import java.io.*;   
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, "20");   
            System.out.println("Serial:" + res);   
            reader.readLine();   
        } catch (IOException ex) {   
        }   
    }   
}