Android Mqtt

Posted 2022-12-04 顾明伟

本文介绍在android上使用mqtt，附上客户端demo和服务器demo。

mqtt资料自行百度

客户端：

别忘了加联网权限

public class MqttService extends Service 

    
    private String host = "tcp://192.168.1.184:1883";
    private String userName = "admin";
    private String passWord = "password";

    private Handler handler;

    private MqttClient client;

    private String myTopic = "test/topic";

    private MqttConnectOptions options;

    private ScheduledExecutorService scheduler;

    public MqttService</span>() 
        super();
    

    @Nullable
    @Override
    public IBinder onBind(Intent intent) 
        return null;
    

    @Override
    public void onCreate() 
        super.onCreate();
        Log.i("Gmw", "onCreate");
        init();

        handler = new Handler() 
            @Override
            public void handleMessage(Message msg) 
                super.handleMessage(msg);
                if (msg.what == 1) 
                    Log.i("Gmw", "" + (String) msg.obj);
                    
                 else if (msg.what == 2) 
                    Log.i("Gmw", "连接成功");
                    try 
                        client.subscribe(myTopic, 1);
                     catch (Exception e) 
                        e.printStackTrace();
                    
                 else if (msg.what == 3) 
                    Log.i("Gmw", "连接失败，系统正在重连");
                
            
        ;

        startReconnect();
    


    private void startReconnect() 
        scheduler = Executors.newSingleThreadScheduledExecutor();
        scheduler.scheduleAtFixedRate(new Runnable() 

            @Override
            public void run() 
                if (!client.isConnected()) 
                    connect();
                
            
        , 0 * 1000, 10 * 1000, TimeUnit.MILLISECONDS);
    

    private void init() 
        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, "lalalalalal",
                    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 MqttCallback() 

                @Override
                public void connectionLost(Throwable cause) 
                    //连接丢失后，一般在这里面进行重连
                    Log.i("Gmw", "connectionLost");
                

                @Override
                public void deliveryComplete(IMqttDeliveryToken token) 
                    //publish后会执行到这里
                    Log.i("Gmw", "deliveryComplete");
                

                @Override
                public void messageArrived(String topicName, MqttMessage message)
                        throws Exception 
                    //subscribe后得到的消息会执行到这里面
                    Log.i("Gmw", "messageArrived");
                    Message msg = new Message();
                    msg.what = 1;
                    msg.obj = topicName + "---" + message.toString();
                    handler.sendMessage(msg);
                
            );
         catch (Exception e) 
            e.printStackTrace();
        
    

    private void connect() 
        new Thread(new Runnable() 

            @Override
            public void run() 
                try 
                    client.connect(options);
                    Message msg = new Message();
                    msg.what = 2;
                    handler.sendMessage(msg);
                 catch (Exception e) 
                    e.printStackTrace();
                    Message msg = new Message();
                    msg.what = 3;
                    handler.sendMessage(msg);
                
            
        ).start();
    

    @Override
    public void onDestroy() 
        super.onDestroy();
        Log.i("Gmw", "onDestroy");
        try 
            scheduler.shutdown();
            client.disconnect();
         catch (MqttException e) 
            e.printStackTrace();
        
    

服务器：

ActiveMQ，下载地址：http://activemq.apache.org/download.html

下载后cd到/bin/macosx/activemq 目录  输入命令：./activemq start 启动服务器项目

打开浏览器 localhost:8161   能启动正常就说明服务器启动成功了

运行客户端代码连接服务器，然后用服务器给客户端推动信息