使用Open API访问CBS接口（不用SDK，java版）

public class CBSAPI {

	private final static Charset UTF8 = StandardCharsets.UTF_8;	
	private final static String SECRET_ID = "改成自己的";	
	private final static String SECRET_KEY = "改成自己的";
	private final static String CT_JSON = "application/json; charset=utf-8";

	public static byte[] hmac256(byte[] key, String msg) throws Exception {
		Mac mac = Mac.getInstance("HmacSHA256");
		SecretKeySpec secretKeySpec = new SecretKeySpec(key, mac.getAlgorithm());
		mac.init(secretKeySpec);
		return mac.doFinal(msg.getBytes(UTF8));
	}

	public static String sha256Hex(String s) throws Exception {
		MessageDigest md = MessageDigest.getInstance("SHA-256");
		byte[] d = md.digest(s.getBytes(UTF8));
		return DatatypeConverter.printHexBinary(d).toLowerCase();
	}

	public static void main(String[] args) throws Exception {
		String service = "cbs";
		String host = "cbs.tencentcloudapi.com";
		String region = "ap-beijing";
		String action = "DescribeDisks";
		String version = "2017-03-12";
		String algorithm = "TC3-HMAC-SHA256";
		String timestamp = String.valueOf(System.currentTimeMillis() / 1000);
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		// 注意时区，否则容易出错
		sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
		String date = sdf.format(new Date(Long.valueOf(timestamp + "000")));

		// ************* 步骤 1：拼接规范请求串 *************
		String httpRequestMethod = "POST";
		String canonicalUri = "/";
		String canonicalQueryString = "";
		String canonicalHeaders = "content-type:application/json; charset=utf-8\n" + "host:" + host + "\n"
				+ "x-tc-action:" + action.toLowerCase() + "\n";
		String signedHeaders = "content-type;host;x-tc-action";

		String payload = "{\"Limit\": 100}";
		String hashedRequestPayload = sha256Hex(payload);
		String canonicalRequest = httpRequestMethod + "\n" + canonicalUri + "\n" + canonicalQueryString + "\n"
				+ canonicalHeaders + "\n" + signedHeaders + "\n" + hashedRequestPayload;
		System.out.println(canonicalRequest);

		// ************* 步骤 2：拼接待签名字符串 *************
		String credentialScope = date + "/" + service + "/" + "tc3_request";
		String hashedCanonicalRequest = sha256Hex(canonicalRequest);
		String stringToSign = algorithm + "\n" + timestamp + "\n" + credentialScope + "\n" + hashedCanonicalRequest;
		System.out.println(stringToSign);

		// ************* 步骤 3：计算签名 *************
		byte[] secretDate = hmac256(("TC3" + SECRET_KEY).getBytes(UTF8), date);
		byte[] secretService = hmac256(secretDate, service);
		byte[] secretSigning = hmac256(secretService, "tc3_request");
		String signature = DatatypeConverter.printHexBinary(hmac256(secretSigning, stringToSign)).toLowerCase();
		System.out.println(signature);

		// ************* 步骤 4：拼接 Authorization *************
		String authorization = algorithm + " " + "Credential=" + SECRET_ID + "/" + credentialScope + ", "
				+ "SignedHeaders=" + signedHeaders + ", " + "Signature=" + signature;
		System.out.println(authorization);

		TreeMap<String, String> headers = new TreeMap<String, String>();
		headers.put("Authorization", authorization);
		headers.put("Content-Type", CT_JSON);
		headers.put("Host", host);
		headers.put("X-TC-Action", action);
		headers.put("X-TC-Timestamp", timestamp);
		headers.put("X-TC-Version", version);
		headers.put("X-TC-Region", region);

		StringBuilder sb = new StringBuilder();
		sb.append("curl -X POST https://").append(host).append(" -H \"Authorization: ").append(authorization)
				.append("\"").append(" -H \"Content-Type: application/json; charset=utf-8\"").append(" -H \"Host: ")
				.append(host).append("\"").append(" -H \"X-TC-Action: ").append(action).append("\"")
				.append(" -H \"X-TC-Timestamp: ").append(timestamp).append("\"").append(" -H \"X-TC-Version: ")
				.append(version).append("\"").append(" -H \"X-TC-Region: ").append(region).append("\"").append(" -d '")
				.append(payload).append("'");
		System.out.println(sb.toString());
	}
}