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以下是一个使用 Java 的HttpURLConnection类生成一个POST请求的示例代码，其 中 AccessKey，sign， timestamp 和 nonce 分别作为查询 参数 ，请求头和请求体 中 的 参数 ： ``` java import java .io.BufferedReader; import java .io.DataOutputStream; import java .io.InputStreamReader; import java .net.HttpURLConnection; import java .net.URL; import java .security.MessageDigest; import java .security.NoSuchAlgorithmException; import java .util.HashMap; import java .util.Map; import java .util.Random; public class ExamplePostRequest { private static final String ACCESS_KEY = "your_access_key_here"; private static final String SECRET_KEY = "your_secret_key_here"; private static final String BASE_URL = "http://example.com/api/post"; public static void main(String[] args) throws Exception { String requestBody = "{\"key1\":\"value1\",\"key2\":\"value2\"}"; String hsPartyId = "your_hsparty_id_here"; String timestamp = Long.toString(System.currentTimeMillis() / 1000L); String nonce = generate Nonce (); // Generate the signature String sign = generate Signature (hsPartyId, timestamp , nonce , requestBody); // Build the query string String queryString = String.format("AccessKey=%s&sign=%s& timestamp =%s& nonce =%s", ACCESS_KEY, sign, timestamp , nonce ); // Build the request URL String requestUrl = String.format("%s?%s", BASE_URL, queryString); // Build the request headers Map<String, String> headers = new HashMap<>(); headers.put("hsPartyId", hsPartyId); // Send the POST request String response = sendPostRequest(requestUrl, headers, requestBody); // Print the response System.out.println(response); private static String sendPostRequest(String requestUrl, Map<String, String> headers, String requestBody) throws Exception { URL url = new URL(requestUrl); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); // Set HTTP method to POST connection.setRequestMethod("POST"); // Set request headers for (Map.Entry<String, String> entry : headers.entrySet()) { connection.setRequestProperty(entry.getKey(), entry.getValue()); // Set content type and length connection.setRequestProperty("Content-Type", "application/json"); connection.setRequestProperty("Content-Length", Integer.toString(requestBody.getBytes().length)); // Enable output and input connection.setDoOutput(true); connection.setDoInput(true); // Send request body DataOutputStream outputStream = new DataOutputStream(connection.getOutputStream()); outputStream.writeBytes(requestBody); outputStream.flush(); outputStream.close(); // Read response BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream())); StringBuilder responseBuilder = new StringBuilder(); String line; while ((line = reader.readLine()) != null) { responseBuilder.append(line); reader.close(); return responseBuilder.toString(); private static String generate Nonce () { // Generate a random alphanumeric string of length 16 String characters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"; StringBuilder nonce Builder = new StringBuilder(); Random random = new Random(); for (int i = 0; i < 16; i++) { int index = random.nextInt(characters.length()); char character = characters.charAt(index); nonce Builder.append(character); return nonce Builder.toString(); private static String generate Signature (String hsPartyId, String timestamp , String nonce , String requestBody) throws NoSuchAlgorithmException { // Concatenate the hsPartyId, timestamp , nonce , and requestBody String concatenatedString = hsPartyId + timestamp + nonce + requestBody; // Generate the SHA-256 hash of the concatenated string using the secret key MessageDigest messageDigest = MessageDigest.getInstance("SHA-256"); messageDigest.update(concatenatedString.getBytes()); messageDigest.update(SECRET_KEY.getBytes()); byte[] digest = messageDigest.digest(); // Convert the hash to a hexadecimal string StringBuilder signature Builder = new StringBuilder(); for (byte b : digest) { String hex = Integer.toHexString(0xff & b); if (hex.length() == 1) { signature Builder.append('0'); signature Builder.append(hex); return signature Builder.toString();