【EMQX实践】SpringBoot集成EMQX客户端组件

import org.eclipse.paho.client.mqttv3.*;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;
 
public class EMQXClientExample {
 
    public static void main(String[] args) {
        String broker = "tcp://your-emqx-host:1883";
        String clientId = "JavaClient";
        MemoryPersistence persistence = new MemoryPersistence();
 
        try {
            MqttClient sampleClient = new MqttClient(broker, clientId, persistence);
            MqttConnectOptions connOpts = new MqttConnectOptions();
            connOpts.setCleanSession(true);
            System.out.println("Connecting to broker: " + broker);
            sampleClient.connect(connOpts);
            System.out.println("Connected");
 
            String topic = "emqx/test";
            String content = "message from Java client";
            MqttMessage message = new MqttMessage(content.getBytes());
            message.setQos(2);
            sampleClient.publish(topic, message);
            System.out.println("Message is published");
 
            sampleClient.disconnect();
            System.out.println("Disconnected");
            System.exit(0);
 
        } catch (MqttException me) {
            System.out.println("reason " + me.getReasonCode());
            System.out.println("msg " + me.getMessage());
            System.out.println("loc " + me.getLocalizedMessage());
            System.out.println("cause " + me.getCause());
            System.out.println("exiting with code " + 1);
        }
    }
}

这段代码演示了如何在Java中使用Eclipse Paho客户端库连接到EMQX，发布一条消息到特定主题，然后断开连接。需要替换your-emqx-host为EMQX服务器的实际IP或主机名，并确保EMQX服务器正在运行，并且网络之间的端口1883（或其他配置的端口）是开放的。