Myeclipse 6.5 注册机

package register;

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