public String EncodeByMD5(String str) throws NoSuchAlgorithmException, UnsupportedEncodingException {
        //确定一个计算方法
        MessageDigest md5=MessageDigest.getInstance("MD5");
        BASE64Encoder base64en=new BASE64Encoder();
        //加密字符串
        String newstr=base64en.encode(md5.digest(str.getBytes("utf-8")));
        return newstr;

    }