Request syntax and signature method V2 for RPC APIs

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.13</version>
</dependency>

import org.apache.http.client.methods.*;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.entity.ByteArrayEntity;
import org.apache.http.entity.ContentType;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URISyntaxException;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.text.SimpleDateFormat;
import java.util.*;

public class Demo {
    private static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss'Z'");
    private static final String ACCESS_KEY_ID = System.getenv("ALIBABA_CLOUD_ACCESS_KEY_ID");
    private static final String ACCESS_KEY_SECRET = System.getenv("ALIBABA_CLOUD_ACCESS_KEY_SECRET");

    public static class SignatureRequest {
        public final String httpMethod;
        public final String host;
        public final String action;
        public final String version;
        public final String canonicalUri = "/";
        public TreeMap<String, Object> headers = new TreeMap<>();
        public TreeMap<String, Object> queryParams = new TreeMap<>();
        public TreeMap<String, Object> body = new TreeMap<>();
        public TreeMap<String, Object> allParams = new TreeMap<>();
        public byte[] bodyByte;

        public SignatureRequest(String httpMethod, String host, String action, String version) {
            this.httpMethod = httpMethod;
            this.host = host;
            this.action = action;
            this.version = version;
            setExtendedHeaders();
        }

        public void setExtendedHeaders() {
            headers.put("AccessKeyId", ACCESS_KEY_ID);
            headers.put("Format", "JSON");
            headers.put("SignatureMethod", "HMAC-SHA1");
            headers.put("SignatureVersion", "1.0");
            headers.put("SignatureNonce", UUID.randomUUID().toString());
            DATE_FORMAT.setTimeZone(new SimpleTimeZone(0, "GMT"));
            headers.put("Timestamp", DATE_FORMAT.format(new Date()));
            headers.put("Action", action);
            headers.put("Version", version);
        }

        public void getAllParams() {
            allParams.putAll(headers);
            if (!queryParams.isEmpty()) {
                allParams.putAll(queryParams);
            }
            if (!body.isEmpty()) {
                allParams.putAll(body);
            }
        }
    }

    public static void main(String[] args) throws IOException {
        // Example 1: Send an API request without a body.
        String httpMethod = "POST";
        String endpoint = "dysmsapi.aliyuncs.com";
        String action = "SendSms";
        String version = "2017-05-25";
        SignatureRequest signatureRequest = new SignatureRequest(httpMethod, endpoint, action, version);
        signatureRequest.queryParams.put("PhoneNumbers", "123XXXXXXXX");
        signatureRequest.queryParams.put("SignName", "XXXXXXX");
        signatureRequest.queryParams.put("TemplateCode", "XXXXXXX");
        signatureRequest.queryParams.put("TemplateParam", "XXXXXXX");

        // Example 2: Send an API request with a body.
        String httpMethod = "POST";
        String endpoint = "mt.aliyuncs.com";
        String action = "TranslateGeneral";
        String version = "2018-10-12";
        SignatureRequest signatureRequest = new SignatureRequest(httpMethod, endpoint, action, version);
        TreeMap<String, Object> body = new TreeMap<>();
        body.put("FormatType", "text");
        body.put("SourceLanguage", "zh");
        body.put("TargetLanguage", "en");
        body.put("SourceText", "Hello");
        body.put("Scene", "general");
        signatureRequest.body = body;
        String formDataToString = formDataToString(body);
        signatureRequest.bodyByte = formDataToString.getBytes(StandardCharsets.UTF_8);
        signatureRequest.headers.put("content-type", "application/x-www-form-urlencoded");*/

        /*// Example 3: Send an API request whose body is a binary file.
        String httpMethod = "POST";
        String endpoint = "ocr-api.cn-hangzhou.aliyuncs.com";
        String action = "RecognizeGeneral";
        String version = "2021-07-07";
        SignatureRequest signatureRequest = new SignatureRequest(httpMethod, endpoint, action, version);
        signatureRequest.bodyByte = Files.readAllBytes(Paths.get("D:\\test.png"));
        signatureRequest.headers.put("content-type", "application/octet-stream");*/

        // Calculate the signature string.
        calculateSignature(signatureRequest);

        // Send a request to test whether the signature string is valid.
        callApi(signatureRequest);
    }

    private static void calculateSignature(SignatureRequest signatureRequest) {
        // Merge header, queryParam, and body into a map that is used to construct a canonicalized query string.
        signatureRequest.getAllParams();

        // Construct a canonicalized query string.
        StringBuilder canonicalQueryString = new StringBuilder();
        signatureRequest.allParams.entrySet().stream().map(entry -> percentEncode(entry.getKey()) + "="
                + percentEncode(String.valueOf(entry.getValue()))).forEachOrdered(queryPart -> {
            if (canonicalQueryString.length() > 0) {
                canonicalQueryString.append("&");
            }
            canonicalQueryString.append(queryPart);
        });
        System.out.println("canonicalQueryString:" + canonicalQueryString);

        // Create a string-to-sign.
        String stringToSign = signatureRequest.httpMethod + "&" + percentEncode(signatureRequest.canonicalUri) + "&" + percentEncode(String.valueOf(canonicalQueryString));
        System.out.println("stringToSign:" + stringToSign);
        // Calculate the signature string.
        String signature = generateSignature(ACCESS_KEY_SECRET, stringToSign);
        System.out.println("signature:" + signature);
        signatureRequest.allParams.put("Signature", signature);
    }

    private static void callApi(SignatureRequest signatureRequest) {
        try {
            String url = String.format("https://%s/", signatureRequest.host);
            URIBuilder uriBuilder = new URIBuilder(url);
            for (Map.Entry<String, Object> entry : signatureRequest.allParams.entrySet()) {
                uriBuilder.addParameter(entry.getKey(), String.valueOf(entry.getValue()));
            }
            HttpUriRequest httpRequest;
            switch (signatureRequest.httpMethod) {
                case "GET":
                    httpRequest = new HttpGet(uriBuilder.build());
                    break;
                case "POST":
                    HttpPost httpPost = new HttpPost(uriBuilder.build());
                    if (signatureRequest.bodyByte != null) {
                        httpPost.setEntity(new ByteArrayEntity(signatureRequest.bodyByte, ContentType.create((String) signatureRequest.headers.get("content-type"))));
                    }
                    httpRequest = httpPost;
                    break;
                case "DELETE":
                    httpRequest = new HttpDelete(uriBuilder.build());
                    break;
                default:
                    System.out.println("Unsupported HTTP method: " + signatureRequest.httpMethod);
                    throw new IllegalArgumentException("Unsupported HTTP method");
            }
            try (CloseableHttpClient httpClient = HttpClients.createDefault(); CloseableHttpResponse response = httpClient.execute(httpRequest)) {
                String result = EntityUtils.toString(response.getEntity(), StandardCharsets.UTF_8);
                System.out.println(result);
            } catch (IOException e) {
                System.out.println("Failed to send request");
                throw new RuntimeException(e);
            }
        } catch (URISyntaxException e) {
            throw new RuntimeException(e);
        }
    }

    private static String formDataToString(Map<String, Object> formData) {
        Map<String, Object> tileMap = new HashMap<>();
        processObject(tileMap, "", formData);
        StringBuilder result = new StringBuilder();
        boolean first = true;
        String symbol = "&";
        for (Map.Entry<String, Object> entry : tileMap.entrySet()) {
            String value = String.valueOf(entry.getValue());
            if (value != null && !value.isEmpty()) {
                if (first) {
                    first = false;
                } else {
                    result.append(symbol);
                }
                result.append(percentEncode(entry.getKey()));
                result.append("=");
                result.append(percentEncode(value));
            }
        }

        return result.toString();
    }

    private static void processObject(Map<String, Object> map, String key, Object value) {
        // No further processing is required for a null value.
        if (value == null) {
            return;
        }
        if (key == null) {
            key = "";
        }
        // If the value is of the List type, traverse the list and perform recursion on each element.
        if (value instanceof List<?>) {
            List<?> list = (List<?>) value;
            for (int i = 0; i < list.size(); ++i) {
                processObject(map, key + "." + (i + 1), list.get(i));
            }
        } else if (value instanceof Map<?, ?>) {
            // If the value is of the Map type, traverse the map and perform recursion on each key-value pair.
            Map<?, ?> subMap = (Map<?, ?>) value;
            for (Map.Entry<?, ?> entry : subMap.entrySet()) {
                processObject(map, key + "." + entry.getKey().toString(), entry.getValue());
            }
        } else {
            // If a key starts with a period (.), remove the period (.) to maintain the continuity of keys.
            if (key.startsWith(".")) {
                key = key.substring(1);
            }
            // If a value is in the byte[] format, convert the value to a string encoded in UTF-8.
            if (value instanceof byte[]) {
                map.put(key, new String((byte[]) value, StandardCharsets.UTF_8));
            } else {
                // Convert the values of other types to strings.
                map.put(key, String.valueOf(value));
            }
        }
    }

    public static String generateSignature(String accessSecret, String stringToSign) {
        try {
            // Create an HMAC-SHA1 key.
            SecretKeySpec signingKey = new SecretKeySpec((accessSecret + "&").getBytes(StandardCharsets.UTF_8), "HmacSHA1");
            // Create and initialize a Mac instance
            Mac mac = Mac.getInstance("HmacSHA1");
            mac.init(signingKey);
            // Calculate the signature string by using the HMAC-SHA1 algorithm.
            byte[] rawHmac = mac.doFinal(stringToSign.getBytes(StandardCharsets.UTF_8));
            return Base64.getEncoder().encodeToString(rawHmac);
        } catch (NoSuchAlgorithmException | InvalidKeyException e) {
            System.out.println("Failed to generate HMAC-SHA1 signature");
            throw new RuntimeException(e);
        }
    }

    public static String percentEncode(String str) {
        if (str == null) {
            throw new IllegalArgumentException("The specified string cannot be null.");
        }
        try {
            return URLEncoder.encode(str, StandardCharsets.UTF_8.name()).replace("+", "%20").replace("*", "%2A").replace("%7E", "~");
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException("UTF-8 encoding is not supported.", e);
        }
    }
}