MQTT协议之订阅及发布

import org.eclipse.paho.client.mqttv3.MqttCallback;  
import org.eclipse.paho.client.mqttv3.MqttDeliveryToken;  
import org.eclipse.paho.client.mqttv3.MqttMessage;  
import org.eclipse.paho.client.mqttv3.MqttTopic;  

/**  
 * 发布消息的回调类  
 *   
 * 必须实现MqttCallback的接口并实现对应的相关接口方法  
 *      ◦CallBack 类将实现 MqttCallBack。每个客户机标识都需要一个回调实例。在此示例中，构造函数传递客户机标识以另存为实例数据。在回调中，将它用来标识已经启动了该回调的哪个实例。  
 *  ◦必须在回调类中实现三个方法：  
 *   
 *  public void messageArrived(MqttTopic topic, MqttMessage message)  
 *  接收已经预订的发布。  
 *   
 *  public void connectionLost(Throwable cause)  
 *  在断开连接时调用。  
 *   
 *  public void deliveryComplete(MqttDeliveryToken token))  
 *      接收到已经发布的 QoS 1 或 QoS 2 消息的传递令牌时调用。  
 *  ◦由 MqttClient.connect 激活此回调。  
 *   
 */    
public class PushCallback implements MqttCallback {  

    public void connectionLost(Throwable cause) {  
        // 连接丢失后，一般在这里面进行重连  
        System.out.println("连接断开，可以做重连");  
    }  

    public void deliveryComplete(MqttDeliveryToken token) {  
        // publish后会执行到这里  
        System.out.println("deliveryComplete---------"+ token.isComplete());  
    }  

    public void messageArrived(MqttTopic topic, MqttMessage message) throws Exception {  
        // subscribe后得到的消息会执行到这里面  
        System.out.println("接收消息主题:"+topic.getName());  
        System.out.println("接收消息Qos:"+message.getQos());  
        System.out.println("接收消息内容:"+new String(message.getPayload()));  
    }  

}  

import org.eclipse.paho.client.mqttv3.MqttClient;  
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;  
import org.eclipse.paho.client.mqttv3.MqttDeliveryToken;  
import org.eclipse.paho.client.mqttv3.MqttException;  
import org.eclipse.paho.client.mqttv3.MqttMessage;  
import org.eclipse.paho.client.mqttv3.MqttPersistenceException;  
import org.eclipse.paho.client.mqttv3.MqttTopic;  
import org.eclipse.paho.client.mqttv3.internal.MemoryPersistence;  

public class Server {  

    public static final String HOST = "tcp://192.168.36.102:1883";  

    public static final String TOPIC = "tokudu/yzq124";  
    private static final String clientid ="server";   

    private MqttClient client;  
    private MqttTopic topic;  
    private String userName = "test";  
    private String passWord = "test";  

    private MqttMessage message;  

    public Server() throws MqttException {  
         //MemoryPersistence设置clientid的保存形式，默认为以内存保存  
        client = new MqttClient(HOST, clientid, new MemoryPersistence());  
        connect();  
    }  

    private void connect() {  
        MqttConnectOptions options = new MqttConnectOptions();  
        options.setCleanSession(false);  
        options.setUserName(userName);  
        options.setPassword(passWord.toCharArray());  
        // 设置超时时间  
        options.setConnectionTimeout(10);  
        // 设置会话心跳时间  
        options.setKeepAliveInterval(20);  
        try {  
               client.setCallback(new PushCallback());  
               client.connect(options);  
               topic = client.getTopic(TOPIC);  
        } catch (Exception e) {  
               e.printStackTrace();  
        }  
    }  

    public void publish(MqttMessage message) throws MqttPersistenceException, MqttException{  
        MqttDeliveryToken token = topic.publish(message);  
        token.waitForCompletion();  
        System.out.println(token.isComplete()+"========");  
    }  

    public static void main(String[] args) throws MqttException {  
        Server server =  new Server();  
        server.message = new MqttMessage();  
        server.message.setQos(1);  
        server.message.setRetained(true);  
        server.message.setPayload("eeeeeaaaaaawwwwww---".getBytes());  
         server.publish(server.message);  
         System.out.println(server.message.isRetained()+"------ratained状态");  
    }  

}  

import java.util.concurrent.Executors;  
import java.util.concurrent.ScheduledExecutorService;  
import java.util.concurrent.TimeUnit;  

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.MqttSecurityException;  
import org.eclipse.paho.client.mqttv3.MqttTopic;  
import org.eclipse.paho.client.mqttv3.internal.MemoryPersistence;  

public class Client {  

    public static final String HOST = "tcp://192.168.36.102:1883";  
    public static final String TOPIC = "tokudu/yzq124";  
    private static final String clientid = "client";  
    private MqttClient client;  
    private MqttConnectOptions options;  
    private String userName = "test";  
    private String passWord = "test";  

    private ScheduledExecutorService scheduler;  

    //重新链接  
    public void startReconnect() {  
        scheduler = Executors.newSingleThreadScheduledExecutor();  
        scheduler.scheduleAtFixedRate(new Runnable() {  
            public void run() {  
                if (!client.isConnected()) {  
                    try {  
                        client.connect(options);  
                    } catch (MqttSecurityException e) {  
                        e.printStackTrace();  
                    } catch (MqttException e) {  
                        e.printStackTrace();  
                    }  
                }  
            }  
        }, 0 * 1000, 10 * 1000, TimeUnit.MILLISECONDS);  
    }  

    private void start() {  
        try {  
            // host为主机名，test为clientid即连接MQTT的客户端ID，一般以客户端唯一标识符表示，MemoryPersistence设置clientid的保存形式，默认为以内存保存  
            client = new MqttClient(HOST, clientid, new MemoryPersistence());  
            // MQTT的连接设置  
            options = new MqttConnectOptions();  
            // 设置是否清空session,这里如果设置为false表示服务器会保留客户端的连接记录，这里设置为true表示每次连接到服务器都以新的身份连接  
            options.setCleanSession(true);  
            // 设置连接的用户名  
            options.setUserName(userName);  
            // 设置连接的密码  
            options.setPassword(passWord.toCharArray());  
            // 设置超时时间 单位为秒  
            options.setConnectionTimeout(10);  
            // 设置会话心跳时间 单位为秒 服务器会每隔1.5*20秒的时间向客户端发送个消息判断客户端是否在线，但这个方法并没有重连的机制  
            options.setKeepAliveInterval(20);  
            // 设置回调  
            client.setCallback(new PushCallback());  
            MqttTopic topic = client.getTopic(TOPIC);  
            //setWill方法，如果项目中需要知道客户端是否掉线可以调用该方法。设置最终端口的通知消息    
            options.setWill(topic, "close".getBytes(), 0, true);  

            client.connect(options);  
            //订阅消息  
            int[] Qos  = {1};  
            String[] topic1 = {TOPIC};  
            client.subscribe(topic1, Qos);  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
    }  
    public void disconnect() {  
         try {  
            client.disconnect();  
        } catch (MqttException e) {  
            e.printStackTrace();  
        }  
    }  



    public static void main(String[] args) throws MqttException {     
        Client client = new Client();  
        client.start();  
    }  

}