/******这里是客户端需要的参数*******/

    public static String deviceName = "0862664D0169757";

    public static String productKey = "a18laywNXCJ";

    public static String secret = "************";



    //用于测试的topic

    private static String subTopic = "/" + productKey + "/" + deviceName + "/get";

    private static String pubTopic = "/" + productKey + "/" + deviceName + "/update";



    public static void StartConnect() throws Exception {

        //客户端设备自己的一个标记，建议是MAC或SN，不能为空，32字符内

        String clientId = "0862664D0169757";//InetAddress.getLocalHost().getHostAddress();



        //设备认证

        Map<String, String> params = new HashMap<String, String>();

        params.put("productKey", productKey); //这个是对应用户在控制台注册的 设备productkey

        params.put("deviceName", deviceName); //这个是对应用户在控制台注册的 设备name

        params.put("clientId", clientId);

        String t = System.currentTimeMillis() + "";

        params.put("timestamp", t);



        //MQTT服务器地址

        String targetServer = "tcp://" + productKey + ".iot-as-mqtt.cn-shanghai.aliyuncs.com:1883";



        //客户端ID格式，两个||之间的内容为设备端自定义的标记，字符范围[0-9][a-z][A-Z]

        String mqttclientId = clientId + "|securemode=2,signmethod=hmacsha1,timestamp=" + t + "|";

        String mqttUsername = deviceName + "&" + productKey; //mqtt用户名格式

        String mqttPassword = "A9E93DE6CFF17C42C90DE890F8BD4DCBF99BC376";//SignUtil.sign(params, secret, "hmacsha1"); //签名



        System.err.println("mqttclientId=" + mqttclientId+"&mqttPassword="+mqttPassword);



        connectMqtt(targetServer, mqttclientId, mqttUsername, mqttPassword, deviceName);

    }



    public static void connectMqtt(String url, String clientId, String mqttUsername,

                                   String mqttPassword, final String deviceName) throws Exception {

        MemoryPersistence persistence = new MemoryPersistence();

        //SSLSocketFactory socketFactory = createSSLSocket();

        final MqttClient sampleClient = new MqttClient(url, clientId, persistence);

        MqttConnectOptions connOpts = new MqttConnectOptions();

        connOpts.setMqttVersion(4); // MQTT 3.1.1

        //connOpts.setSocketFactory(socketFactory);



        //设置是否自动重连

        //connOpts.setAutomaticReconnect(true);



        //如果是true，那么清理所有离线消息，即QoS1或者2的所有未接收内容

        connOpts.setCleanSession(false);



        connOpts.setUserName(mqttUsername);

        connOpts.setPassword(mqttPassword.toCharArray());

        connOpts.setKeepAliveInterval(65);



        //LogUtil.print(clientId + "进行连接, 目的地: " + url);

        sampleClient.connect(connOpts);



        sampleClient.setCallback(new MqttCallback() {

            @Override

            public void connectionLost(Throwable cause) {

                System.out.println("连接失败,原因:" + cause);

                cause.printStackTrace();

            }



            @Override

            public void messageArrived(String topic, MqttMessage message) throws Exception {

                System.out.println("接收到消息,来至Topic [" + topic + "] , 内容是:["

                        + new String(message.getPayload(), "UTF-8") + "],  ");

            }



            @Override

            public void deliveryComplete(IMqttDeliveryToken token) {

                //如果是QoS0的消息，token.resp是没有回复的

                System.out.println("消息发送成功! " + ((token == null || token.getResponse() == null) ? "null"

                        : token.getResponse().getKey()));

            }

        });