OAuthSignatureGenerate.java

protected Map<String, String> buildRequestParameters(Const.HttpMethod httpMethod, String requestPath,
		SyncStore store) {
	TreeMap<String, String> params = new TreeMap<String, String>();
	params.put("oauth_consumer_key", store.getConsumerKey());
	params.put("oauth_nonce", generateOAuthNonce(32));
	params.put("oauth_signature_method", "HMAC-SHA1");
	params.put("oauth_timestamp", String.valueOf(System.currentTimeMillis() / 1000L));

	String signature = buildOAuthSignature(httpMethod.name(), requestPath, params, store.getConsumerSecret());
	params.put("oauth_signature", signature);
	return params;
}

private String generateOAuthNonce(int length) {
	return RandomStringUtils.randomAlphanumeric(length);
}

private String buildOAuthSignature(String httpMethod, String requestUri, Map<String, String> params, String secret) {
	try {
		String encodedRequestUri = URLEncoder.encode(requestUri, "UTF-8");
		ArrayList<String> encodedParams = new ArrayList<String>();

		for (String key : params.keySet()) {
			String encodedKey = URLEncoder.encode(key, "UTF-8");
			String encodedValue = URLEncoder.encode(params.get(key), "UTF-8");
			encodedParams.add(encodedKey + "=" + encodedValue);
		}

		String paramsString = StringUtils.join(encodedParams, "&");
		String encodedParamsString = URLEncoder.encode(paramsString, "UTF-8");
		String stringToSign = httpMethod + "&" + encodedRequestUri + "&" + encodedParamsString;
		log.info("String to sign: " + stringToSign);
		String signature = calculateRFC2104HMAC(stringToSign, secret + "&");
		return URLEncoder.encode(signature, "UTF-8");
	} catch (Exception e) {
		e.printStackTrace();
		return null;
	}
}

public static String calculateRFC2104HMAC(String data, String key)
		throws SignatureException, NoSuchAlgorithmException, InvalidKeyException {
	String alg = "HmacSHA1";
	SecretKeySpec signingKey = new SecretKeySpec(key.getBytes(), alg);
	Mac mac = Mac.getInstance(alg);
	mac.init(signingKey);
	return hmacToString(mac.doFinal(data.getBytes()));
}

private static String hmacToString(byte[] bytes) {
	return Base64.getEncoder().encodeToString(bytes);
}