给我一个使用EMQX的jwt认证方式调用/api/v5/authentication/{id}/users的java代码示例

好的，以下是使用EMQX的jwt认证方式调用/api/v5/authentication/{id}/users的java代码示例，请您参考：

import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.util.Base64;
import java.util.Date;
import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;
import org.json.JSONObject;

public class EMQXApiCall {
    
    // EMQX相关信息
    private static final String EMQX_HOST = "your-emqx-host";
    private static final String EMQX_PORT = "your-emqx-port";
    private static final String EMQX_API_URL = "http://" + EMQX_HOST + ":" + EMQX_PORT + "/api/v5/authentication/{id}/users";
    private static final String EMQX_ID = "your-emqx-id";
    
    // jwt相关信息
    private static final String JWT_SECRET = "your-jwt-secret";
    private static final String JWT_ISSUER = "your-jwt-issuer";
    
    public static void main(String[] args) throws Exception {
        // 构建jwt
        String token = generateJwt();
        
        // 构建Http请求
        HttpClient httpClient = HttpClientBuilder.create().build();
        HttpGet httpGet = new HttpGet(EMQX_API_URL);
        httpGet.setHeader("Authorization", "Bearer " + token);
        
        // 发送Http请求
        HttpResponse response = httpClient.execute(httpGet);
        String responseBody = EntityUtils.toString(response.getEntity());
        System.out.println(responseBody);
    }
    
    /**
     * 构建Jwt，使用HmacSHA256加密方式。
     */
    private static String generateJwt() throws NoSuchAlgorithmException, InvalidKeyException, UnsupportedEncodingException {
        long timestamp = new Date().getTime() / 1000;
        String headerAndPayload = Base64.getUrlEncoder().encodeToString(("{\"alg\": \"HS256\", \"typ\": \"JWT\", \"iss\": \"" + JWT_ISSUER + "\", \"exp\": " + (timestamp + 3600) + "}").getBytes())
                + "." + Base64.getUrlEncoder().encodeToString(("{\"client_id\": \"" + EMQX_ID + "\", \"scope\": \"mqtt.publish\", \"exp\": " + (timestamp + 3600) + "}").getBytes());
        Mac hmac = Mac.getInstance("HmacSHA256");
        hmac.init(new SecretKeySpec(JWT_SECRET.getBytes(), "HmacSHA256"));
        String signature = Base64.getUrlEncoder().encodeToString(hmac.doFinal(headerAndPayload.getBytes("UTF-8")));
        return headerAndPayload + "." + signature;
    }
}

希望这段代码对您有所帮助！