使用PAHO订阅和阅读MQTT消息

您将在代理有时间将消息发送回之前关闭客户端。

另外，您不需要2个客户端实例，只需一个实例就可以发送和接收。

我已经稍微修改了您的代码，现在它将继续运行并接收消息，直到您将其杀死。

import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;import org.eclipse.paho.client.mqttv3.MqttCallback;import org.eclipse.paho.client.mqttv3.MqttClient;import org.eclipse.paho.client.mqttv3.MqttException;import org.eclipse.paho.client.mqttv3.MqttMessage;public class PahoDemo implements MqttCallback {MqttClient client;public PahoDemo() {}public static void main(String[] args) {    new PahoDemo().doDemo();}public void doDemo() {    try {        client = new MqttClient("tcp://192.168.118.11:1883", "Sending");        client.connect();        client.setCallback(this);        client.subscribe("foo");        MqttMessage message = new MqttMessage();        message.setPayload("A single message from my computer fff"     .getBytes());        client.publish("foo", message);    } catch (MqttException e) {        e.printStackTrace();    }}@Overridepublic void connectionLost(Throwable cause) {    // TODO Auto-generated method stub}@Overridepublic void messageArrived(String topic, MqttMessage message)        throws Exception { System.out.println(message);   }@Overridepublic void deliveryComplete(IMqttDeliveryToken token) {    // TODO Auto-generated method stub}}

编辑：添加了丢失的内容

client.setCallback(this)