MD5加密类方法

package com.shkj.android.utils;

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

/**
 * md5加密
 * @author admin
 */
public class MD5 {
 private static final String ALGORITHM = "MD5";

 private static char sHexDigits[] = { '0', '1', '2', '3', '4', '5', '6',
   '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
 private static MessageDigest sDigest;

 static {
  try {
   sDigest = MessageDigest.getInstance(ALGORITHM);
  } catch (NoSuchAlgorithmException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
 }

 private MD5() {
 }
 
 //调用此方法，直接传字符串即可加密
 final public static String encode(String source) {
  byte[] btyes = source.getBytes();
  byte[] encodedBytes = sDigest.digest(btyes);

  return hexString(encodedBytes);
 }
 
 public static String hexString(byte[] source) {
  if (source == null || source.length <= 0) {
   return "";
  }

  final int size = source.length;
  final char str[] = new char[size * 2];
  int index = 0;
  byte b;
  for (int i = 0; i < size; i++) {
   b = source[i];
   str[index++] = sHexDigits[b >>> 4 & 0xf];
   str[index++] = sHexDigits[b & 0xf];
  }
  return new String(str);
 }
}