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
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");
}
}