myeclipse 注册码生成

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 = decode(dx); 
  String code = new StringBuilder(need).append(String.valueOf(suf)) 
    .toString(); 
  return 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) { 
  } 
} 
}