Java的MD5实现

rfcs: http://www.faqs.org/rfcs/rfc1321.html

import java.security.*;
import java.security.spec.*;

public class MD5{
    public String convert(String s){
        char hexChars[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
        try {
            byte[] bytes = s.getBytes();
            MessageDigest md = MessageDigest.getInstance("MD5");
            md.update(bytes);
            bytes = md.digest();
            int j = bytes.length;
            char[] chars = new char[j * 2];
            int k = 0;
            for (int i = 0; i < bytes.length; i++) {
                byte b = bytes[i];
                chars[k++] = hexChars[b >>> 4 & 0xf];
                chars[k++] = hexChars[b & 0xf];
            }
            return new String(chars);
        }
        catch (Exception e){
            return null;
        }
    }
   
    public static void main(String[] args){
        System.out.println(new MD5().convert("0123456789"));       
    }