curl -X POST https://cvm.tencentcloudapi.com \\
-H "Authorization: TC3-HMAC-SHA256 Credential=AKIDz8krbsJ5**********mLPx3EXAMPL/2019-02-25/cvm/tc3_request, SignedHeaders=content-type;host, Signature=72e494ea8******************************************a96525168" \\
-H "Content-Type: application/json; charset=utf-8" \\
-H "Host: cvm.tencentcloudapi.com" \\
-H "X-TC-Action: DescribeInstances" \\
-H "X-TC-Timestamp: 1551113065" \\
-H "X-TC-Version: 2017-03-12" \\
-H "X-TC-Region: ap-guangzhou" \\
-d '{"Limit": 1, "Filters": [{"Values": ["\\u672a\\u547d\\u540d"], "Name": "instance-name"}]}'

CanonicalRequest =
    HTTPRequestMethod + '\\n' +
    CanonicalURI + '\\n' +
    CanonicalQueryString + '\\n' +
    CanonicalHeaders + '\\n' +
    SignedHeaders + '\\n' +
    HashedRequestPayload

POST
/

content-type:application/json; charset=utf-8
host:cvm.tencentcloudapi.com

content-type;host
35e9c5b0e3ae67532d3c9f17ead6c90222632e5b1ff7f6e89887f1398934f064

StringToSign =
    Algorithm + \\n +
    RequestTimestamp + \\n +
    CredentialScope + \\n +
    HashedCanonicalRequest

TC3-HMAC-SHA256
1551113065
2019-02-25/cvm/tc3_request
5ffe6a04c0664d6b969fab9a13bdab201d63ee709638e2749d62a09ca18d7031

SecretKey = "Gu5t9xGAR***********EXAMPLE"
byte[] secretDate = hmac256(("TC3" + SecretKey).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);

String Authorization =
    Algorithm + ' ' +
    'Credential=' + SecretId + '/' + CredentialScope + ', ' +
    'SignedHeaders=' + SignedHeaders + ', ' +
    'Signature=' + Signature

TC3-HMAC-SHA256 Credential=AKIDz8krbsJ5**********mLPx3EXAMPL/2019-02-25/cvm/tc3_request, SignedHeaders=content-type;host, Signature=72e494ea8******************************************a96525168

POST https://cvm.tencentcloudapi.com/
Authorization: TC3-HMAC-SHA256 Credential=AKIDz8krbsJ5**********mLPx3EXAMPL/2019-02-25/cvm/tc3_request, SignedHeaders=content-type;host, Signature=72e494ea8******************************************a96525168
Content-Type: application/json; charset=utf-8
Host: cvm.tencentcloudapi.com
X-TC-Action: DescribeInstances
X-TC-Version: 2017-03-12
X-TC-Timestamp: 1551113065
X-TC-Region: ap-guangzhou

{"Limit": 1, "Filters": [{"Values": ["\\u672a\\u547d\\u540d"], "Name": "instance-name"}]}

import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.security.MessageDigest;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;
import java.util.TreeMap;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;

public class TencentCloudAPITC3Demo {
    private final static Charset UTF8 = StandardCharsets.UTF_8;
    private final static String SECRET_ID = "AKIDz8krbsJ5**********mLPx3EXAMPL";
    private final static String SECRET_KEY = "Gu5t9xGAR***********EXAMPLE";
    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 = "cvm";
        String host = "cvm.tencentcloudapi.com";
        String region = "ap-guangzhou";
        String action = "DescribeInstances";
        String version = "2017-03-12";
        String algorithm = "TC3-HMAC-SHA256";
        String timestamp = "1551113065";
        //String timestamp = String.valueOf(System.currentTimeMillis() / 1000);
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        // タイムゾーンに注意してください。さもないとエラーが発生しやすくなります
        sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
        String date = sdf.format(new Date(Long.valueOf(timestamp + "000")));

        // ************* ステップ 1：正規リクエスト文字列の連結 *************
        String httpRequestMethod = "POST";
        String canonicalUri = "/";
        String canonicalQueryString = "";
        String canonicalHeaders = "content-type:application/json; charset=utf-8\\n" + "host:" + host + "\\n";
        String signedHeaders = "content-type;host";

        String payload = "{\\"Limit\\": 1, \\"Filters\\": [{\\"Values\\": [\\"\\\\u672a\\\\u547d\\\\u540d\\"], \\"Name\\": \\"instance-name\\"}]}";
        String hashedRequestPayload = sha256Hex(payload);
        String canonicalRequest = httpRequestMethod + "\\n" + canonicalUri + "\\n" + canonicalQueryString + "\\n"
                + canonicalHeaders + "\\n" + signedHeaders + "\\n" + hashedRequestPayload;
        System.out.println(canonicalRequest);

        // ************* ステップ 2：署名対象文字列を連結する *************
        String credentialScope = date + "/" + service + "/" + "tc3_request";
        String hashedCanonicalRequest = sha256Hex(canonicalRequest);
        String stringToSign = algorithm + "\\n" + timestamp + "\\n" + credentialScope + "\\n" + hashedCanonicalRequest;
        System.out.println(stringToSign);

        // ************* ステップ 3：署名を計算する *************
        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);

        // ************* ステップ 4：Authorizationを連結する *************
        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());
    }
}

{
    'Action' : 'DescribeInstances',
    'InstanceIds.0' : 'ins-09dx96dg',
    'Limit' : 20,
    'Nonce' : 11886,  
    'Offset' : 0,
    'Region' : 'ap-guangzhou',
    'SecretId' : 'AKIDz8krbsJ5**********mLPx3EXAMPL',
    'Timestamp' : 1465185768,
    'Version': '2017-03-12',
}

Action=DescribeInstances&InstanceIds.0=ins-09dx96dg&Limit=20&Nonce=11886&Offset=0&Region=ap-guangzhou&SecretId=AKIDz8krbsJ5**********mLPx3EXAMPL&Timestamp=1465185768&Version=2017-03-12

GETcvm.tencentcloudapi.com/?Action=DescribeInstances&InstanceIds.0=ins-09dx96dg&Limit=20&Nonce=11886&Offset=0&Region=ap-guangzhou&SecretId=AKIDz8krbsJ5**********mLPx3EXAMPL&Timestamp=1465185768&Version=2017-03-12

import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.Base64;

/**
 *
 * [Hmac-SHA1 署名アルゴリズム]
 * @String  encryptText [暗号化文字ソース文字列]
 * @String  encryptKey  [暗号化シークレットキー]
 * @return [シグネチャ値]
 */
public class HmacSHA1 {
    private static final String MAC_NAME = "HmacSHA1";
    public static final String ENCODING = "UTF-8";
    //署名方法
    public static String HmacSHA1Encrypt(String s,String secret_key ) throws Exception{
        byte[] data = encryptKey.getBytes( ENCODING );
        SecretKey secretKey = new SecretKeySpec( data, MAC_NAME );
        Mac mac = Mac.getInstance( MAC_NAME );
        mac.init( secretKey );
        byte[] text = encryptText.getBytes( ENCODING );
        byte[] digest = mac.doFinal( text );
        return new String(Base64.encodeBase64(digest));
    }
}
String secret_key = "Gu5t9xGAR***********EXAMPLE";
String s = "GETcvm.tencentcloudapi.com/?Action=DescribeInstances&InstanceIds.0=ins-09dx96dg&Limit=20&Nonce=11886&Offset=0&Region=ap-guangzhou&SecretId=AKIDz8krbsJ5**********mLPx3EXAMPL&Timestamp=1465185768&Version=2017-03-12";
//最終署名文字列
String Signature = new HmacSHA1();
System.out.println(Signature)

# 実際の呼び出し、成功した場合、消費型APIであれば課金が発生する可能性があります（ここではPython言語を例としてgetリクエストを送信します）
resp = requests.get("https://" + endpoint, params=data)
print(resp.url)

最終的に得られるリクエスト文字列は
https://cvm.tencentcloudapi.com/?Action=DescribeInstances&InstanceIds.0=ins-09dx96dg&Limit=20&Nonce=11886&Offset=0&Region=ap-guangzhou&SecretId=AKIDz8krbsJ5**********mLPx3EXAMPL&Signature=EliP9YW3pW28FpsEdkXt%2F%2BWcGeI%3D&Timestamp=1465185768&Version=2017-03-12

import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.Random;
import java.util.TreeMap;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;

public class TencentCloudAPIDemo {
    private final static String CHARSET = "UTF-8";

    public static String sign(String s, String key, String method) throws Exception {
        Mac mac = Mac.getInstance(method);
        SecretKeySpec secretKeySpec = new SecretKeySpec(key.getBytes(CHARSET), mac.getAlgorithm());
        mac.init(secretKeySpec);
        byte[] hash = mac.doFinal(s.getBytes(CHARSET));
        return DatatypeConverter.printBase64Binary(hash);
    }

    public static String getStringToSign(TreeMap<String, Object> params) {
        StringBuilder s2s = new StringBuilder("GETcvm.tencentcloudapi.com/?");
        // 署名時にはパラメータの辞書順（ASCIIコード昇順）ソートが必要であり、ここではTreeMapを使用して順序を保証します。
        for (String k : params.keySet()) {
            s2s.append(k).append("=").append(params.get(k).toString()).append("&");
        }
        return s2s.toString().substring(0, s2s.length() - 1);
    }

    public static String getUrl(TreeMap<String, Object> params) throws UnsupportedEncodingException {
        StringBuilder url = new StringBuilder("https://cvm.tencentcloudapi.com/?");
        // 実際のリクエストurlでは、パラメータの順序に要求はありません。
        for (String k : params.keySet()) {
            // リクエスト文字列に対してurlencodeを行う必要があります。keyはすべて英字であるため、ここではそのvalueのみをurlencodeします。
            url.append(k).append("=").append(URLEncoder.encode(params.get(k).toString(), CHARSET)).append("&");
        }
        return url.toString().substring(0, url.length() - 1);
    }

    public static void main(String[] args) throws Exception {
        TreeMap<String, Object> params = new TreeMap<String, Object>(); // TreeMapは自動的にソートできます
        // 実際の呼び出し時には乱数を使用する必要があります。例えば：params.put("Nonce", new Random().nextInt(java.lang.Integer.MAX_VALUE));
        params.put("Nonce", 11886); // 共通パラメータ
        // 実際の呼び出し時にはシステムの現在時刻を使用する必要があります。例えば：   params.put("Timestamp", System.currentTimeMillis() / 1000);
        params.put("Timestamp", 1465185768); // 共通パラメータ
        params.put("SecretId", "AKIDz8krbsJ5**********mLPx3EXAMPL"); // 共通パラメータ
        params.put("Action", "DescribeInstances"); // 共通パラメータ
        params.put("Version", "2017-03-12"); // 共通パラメータ
        params.put("Region", "ap-guangzhou"); // 共通パラメータ
        params.put("Limit", 20); // 業務パラメータ
        params.put("Offset", 0); // 業務パラメータ
        params.put("InstanceIds.0", "ins-09dx96dg"); // 業務パラメータ
        params.put("Signature", sign(getStringToSign(params), "Gu5t9xGAR***********EXAMPLE", "HmacSHA1")); // 共通パラメータ
        System.out.println(getUrl(params));
    }
}