如何在 HiveMQ Client 中获取客户端连接信息？ (MQTT)

Question

我正在编写一个主类，它将创建一些客户端并测试它们的订阅和发布。我想显示客户端连接的信息，例如连接的数据和时间、clientId、用于连接的 clientIP，无论它们是否正常连接。我不熟悉使用像 Logger 这样的工具，所以我不确定我会如何做到这一点。我留下了 HiveMQ 社区版（代理）和客户端的链接。我想在 HiveMQ 客户端项目的主类中显示此信息，但社区版中有一个名为 event.log 的日志文件，其中包含我想要显示的信息类型。我在下面留下了一张图片。

HiveMQ：

https://github.com/hivemq/hivemq-community-edition https://github.com/hivemq/hivemq-mqtt-client

在 hivemq-community-edition 中有一个 event.log 文件，其中包含我想要显示的信息。它是在我将项目构建为 Gradle 项目时生成的，因此除非您将其导入 Eclipse 并使用 Gradle 内置，否则无法找到它，因此我留下了它的屏幕截图。

HiveMQ 客户端主类中的代码：

package com.main;

import java.util.UUID;

import com.hivemq.client.mqtt.MqttGlobalPublishFilter;
import com.hivemq.client.mqtt.datatypes.MqttQos;
import com.hivemq.client.mqtt.mqtt5.Mqtt5BlockingClient;
import com.hivemq.client.mqtt.mqtt5.Mqtt5BlockingClient.Mqtt5Publishes;
import com.hivemq.client.mqtt.mqtt5.Mqtt5Client;
import com.hivemq.client.mqtt.mqtt5.message.publish.Mqtt5Publish;
import java.util.logging.Logger;
import java.util.NoSuchElementException;

import java.util.logging.Level;
import java.util.concurrent.TimeUnit;


public class Main {

    private static final Logger LOGGER = Logger.getLogger(Main.class.getName());  // Creates a logger instance 


    public static void main(String[] args) {

                Mqtt5BlockingClient client1 = Mqtt5Client.builder()
            .identifier(UUID.randomUUID().toString()) // the unique identifier of the MQTT client. The ID is randomly generated between 
            .serverHost("localhost")  // the host name or IP address of the MQTT server. Kept it 0.0.0.0 for testing. localhost is default if not specified.
            .serverPort(1883)  // specifies the port of the server
            .buildBlocking();  // creates the client builder

            client1.connect();  // connects the client
            System.out.println("Client1 Connected");
            System.out.println(client1.toString());


            String testmessage = "How is it going!";
            byte[] messagebytesend = testmessage.getBytes();   // stores a message as a byte array to be used in the payload 

    try {  

        Mqtt5Publishes publishes = client1.publishes(MqttGlobalPublishFilter.ALL);  // creates a "publishes" instance thats used to queue incoming messages

            client1.subscribeWith()  // creates a subscription 
            .topicFilter("test1/#")  // filters to receive messages only on this topic (# = Multilevel wild card, + = single level wild card)
            .qos(MqttQos.AT_LEAST_ONCE)  // Sets the QoS to 2 (At least once) 
            .send(); 
            System.out.println("The client1 has subscribed");


            client1.publishWith()  // publishes the message to the subscribed topic 
            .topic("test/pancakes/topic")   // publishes to the specified topic
            .qos(MqttQos.AT_LEAST_ONCE)  
            .payload(messagebytesend)  // the contents of the message 
            .send();
            System.out.println("The client1 has published");


            Mqtt5Publish receivedMessage = publishes.receive(5,TimeUnit.SECONDS).get(); // receives the message using the "publishes" instance waiting up to 5 seconds                                                                          // .get() returns the object if available or throws a NoSuchElementException 


         byte[] tempdata = receivedMessage.getPayloadAsBytes();    // converts the "Optional" type message to a byte array 
         System.out.println();
         String getdata = new String(tempdata); // converts the byte array to a String 
         System.out.println(getdata);


    }

    catch (InterruptedException e) {    // Catches interruptions in the thread 
        LOGGER.log(Level.SEVERE, "The thread was interrupted while waiting for a message to be received", e);
        }

    catch (NoSuchElementException e){
        System.out.println("There are no received messages");   // Handles when a publish instance has no messages 
    }

    client1.disconnect();  
    System.out.println("Client1 Disconnected");

    }

}

Answer 1

您可以通过getConfig例如方法获取有关客户端的信息

Mqtt5ClientConfig config = client.getConfig();
config.getClientIdentifier();

要获取当前连接的信息，请使用getConnectionConfig 例如

Optional<Mqtt5ClientConnectionConfig> connectionConfig = config.getConnectionConfig();
if (connectionConfig.isPresent()) {
    MqttClientTransportConfig transportConfig = connectionConfig.get().getTransportConfig();
}

您还可以使用在客户端连接或断开连接时收到通知的侦听器，例如

Mqtt5Client.builder()
        .addConnectedListener(context -> System.out.println("connected"))
        .addDisconnectedListener(context -> System.out.println("disconnected"))
        ...