[Android]对字符串进行MD5加密

 /**
      * 将字符串转成MD5值
      *
      * @param string
      * @return
      */
     public static String stringToMD5(String string) {
         byte[] hash;  

         try {
             hash = MessageDigest.getInstance("MD5").digest(string.getBytes("UTF-8"));
         } catch (NoSuchAlgorithmException e) {
             e.printStackTrace();
             return null;
         } catch (UnsupportedEncodingException e) {
             e.printStackTrace();
             return null;
         }  

         StringBuilder hex = new StringBuilder(hash.length * 2);
         for (byte b : hash) {
             if ((b & 0xFF) < 0x10)
                 hex.append("0");
             hex.append(Integer.toHexString(b & 0xFF));
         }  

         return hex.toString();
     }