EMQX,MQTT的簡單使用

//第一步導包

<dependencies>
    <dependency>
        <groupId>org.eclipse.paho</groupId>
        <artifactId>org.eclipse.paho.client.mqttv3</artifactId>
        <version>1.2.2</version>
    </dependency>
</dependencies>

//第二部寫一個訂閱端 這里連接的路徑你的自己啟動一個EMQX服務器 具體怎么裝 百度。  有Linux版本和windows版本

package mqtt2;

import org.eclipse.paho.client.mqttv3.*;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;

/**
 *訂閱端
 */
public class SubscribeSample {

    public static void main(String[] args) throws MqttException {
        String HOST = "tcp://127.0.0.1:1883";
        String TOPIC = "testtopic/test";
        int qos = 1;
        String clientid = "subClient";
        String userName = "test";
        String passWord = "test";
        try {
            // host為主機名，test為clientid即連接MQTT的客戶端ID，一般以客戶端唯一標識符表示，MemoryPersistence設置clientid的保存形式，默認為以內存保存
            MqttClient client = new MqttClient(HOST, clientid, new MemoryPersistence());
            // MQTT的連接設置
            MqttConnectOptions options = new MqttConnectOptions();
            // 設置是否清空session,這里如果設置為false表示服務器會保留客戶端的連接記錄，這里設置為true表示每次連接到服務器都以新的身份連接
            options.setCleanSession(true);
            // 設置連接的用戶名
            options.setUserName(userName);
            // 設置連接的密碼
            options.setPassword(passWord.toCharArray());
            // 設置超時時間 單位為秒
            options.setConnectionTimeout(10);
            // 設置會話心跳時間 單位為秒 服務器會每隔1.5*20秒的時間向客戶端發送個消息判斷客戶端是否在線，但這個方法並沒有重連的機制
            options.setKeepAliveInterval(20);
            // 設置回調函數
            client.setCallback(new MqttCallback() {

                public void connectionLost(Throwable cause) {
                    System.out.println("connectionLost");
                }

                public void messageArrived(String topic, MqttMessage message) throws Exception {
                    System.out.println("topic:"+topic);
                    System.out.println("Qos:"+message.getQos());
                    System.out.println("----------");
                    ChuliDemo.ChuliDemo(new String(message.getPayload()));
                    System.out.println("message content:"+new String(message.getPayload()));
                    
                }

                public void deliveryComplete(IMqttDeliveryToken token) {
                    System.out.println("deliveryComplete---------"+ token.isComplete());
                }

            });
            client.connect(options);
            //訂閱消息
            client.subscribe(TOPIC, qos);

            // 消息發布所需參數
            MqttMessage message = new MqttMessage("helloworld".getBytes());
            message.setQos(qos);
            client.publish(TOPIC, message);
            System.out.println("Message published");

            //這里已開啟他就會自動關閉了
//            client.disconnect();
//            client.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}



//可以使用MQTT當發布端 也可以自己用java寫一個發布端

package mqtt2;

import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttException;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;

/**
 *發布端
 */
public class PublishSample {
    public static void main(String[] args) {

        String topic = "testtopic/test";
        String content = "hello 哈哈";
        int qos = 1;
        String broker = "tcp://127.0.0.1:1883";
        String userName = "admin";
        String password = "public";
        String clientId = "pubClient";
        // 內存存儲
        MemoryPersistence persistence = new MemoryPersistence();

        try {
            // 創建客戶端
            MqttClient sampleClient = new MqttClient(broker, clientId, persistence);
            // 創建鏈接參數
            MqttConnectOptions connOpts = new MqttConnectOptions();
            // 在重新啟動和重新連接時記住狀態
            connOpts.setCleanSession(false);
            // 設置連接的用戶名
            connOpts.setUserName(userName);
            connOpts.setPassword(password.toCharArray());
            // 建立連接
            sampleClient.connect(connOpts);
            // 創建消息
            MqttMessage message = new MqttMessage(content.getBytes());
            // 設置消息的服務質量
            message.setQos(qos);
            // 發布消息
            sampleClient.publish(topic, message);
            // 斷開連接
            sampleClient.disconnect();
            // 關閉客戶端
            sampleClient.close();
        } 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("excep " + me);
            me.printStackTrace();
        }
    }
}

這里可以嘗試裝兩個工具來進行測試 EMQX和MQTTX