实现MD5验证的类

package test;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class md5 {
// public md5(String newsource) {
//  // TODO Auto-generated constructor stub
// }

 public String md5(String source){
  String dest = null;
  try {
   MessageDigest md5 = MessageDigest.getInstance("MD5");
   char[] charArray = source.toCharArray();    
   byte[] byteArray = new byte[charArray.length];   
   for (int i=0; i<charArray.length; i++)
    byteArray[i] = (byte) charArray[i];   
   byte[] md5Bytes = md5.digest(byteArray);
   StringBuffer hexValue = new StringBuffer();
   for (int i=0; i<md5Bytes.length; i++)
   {
    int val = ((int) md5Bytes[i] ) & 0xff; 
    if (val < 16) hexValue.append("0");
    hexValue.append(Integer.toHexString(val));
   }
   dest = hexValue.toString();
  } catch (NoSuchAlgorithmException e) {
   e.printStackTrace();
  }
  return dest;
 }
 
 public static void main(String[] args){
  String source = "nwt123456";
  String newsource = "nwt"+source;
  md5 md  = new md5();
  md.md5(source);
//  md5 m1 = new md5(newsource);
  md5 m2 = new md5();
  m2.md5(newsource);
  System.out.println(source+"---"+md.md5(source));
  System.out.println(newsource+"---"+m2.md5(newsource));

 }
}