java.lang.ClassNotFoundException: org.apache.commons.codec.binary.Base64

Здесь я передаю три параметра методу знака. В этой строке

signature = new String (Base64.encodeBase64 (mac.doFinal (data.getBytes (UTF_8_Encoding))));

Я получаю сообщение об ошибке:

SEVERE: Servlet.service () для сервлета [com.asp.amz.amzServlet] в контексте с путем [/ amazon] выбросило исключение [Выполнение сервлета вызвало исключение] с первопричиной java.lang.ClassNotFoundException: org.apache.commons.codec.binary.Base64

String Key = "z/0qfiE+ScjxHy2gSwmHqP0rZ6fT9zhVgsNt";
String signatureMethod = "HmacSHA256";
String data = "sandbox.amazon.com/cobranded-ui/actions/start?callerKey=AKIAJZOKEUCXF7RKSCNA&callerReference=callerReferenceSingleUse&currencyCode=USD&paymentReason=HarryPotter%201-5%20DVD%20set&pipelineName=SingleUse&returnURL=http%3A%2F%2Flocalhost%3A8888%2Famazon&signatureMethod=HmacSHA256&signatureVersion=2&transactionAmount=5&version=2009-01-09";

    private static String sign(String data, String key, String signatureMethod) throws SignatureException
    {
        System.out.println(" In sign block ");
        String signature = "";
        try {
            System.out.println(" In sign Try block ");
            Mac mac = Mac.getInstance(signatureMethod);
            mac.init(new SecretKeySpec(key.getBytes(), signatureMethod));
            signature = new String(Base64.encodeBase64(mac.doFinal(data.getBytes(UTF_8_Encoding))));
            System.out.println(" In sign Try block ");
        } catch (Exception e) {
            System.out.println(" In sign catch block ");
            throw new SignatureException("Failed to generate signature: " + e.getMessage(), e);         
        }
        System.out.println(" End sign block " + signature);
        return signature;
    }