连接丢失 (32109) - java.io.EOFException (MqttAndroidClient)

Question

P.S。请在得出任何结论之前阅读整个问题。

每当调用 connect 方法时，我都会收到以下异常：

Connection lost (32109) - java.io.EOFException at org.eclipse.paho.client.mqttv3.internal.CommsReceiver.run(CommsReceiver.java:146) at java.lang.Thread.run(Thread.java:818) Caused by: java.io.EOFException at java.io.DataInputStream.readByte(DataInputStream.java:77) at org.eclipse.paho.client.mqttv3.internal.wire.MqttInputStream.readMqttWireMessage(MqttInputStream.java:65) at org.eclipse.paho.client.mqttv3.internal.CommsReceiver.run(CommsReceiver.java:107)

我尝试了几个代码片段，但它们都引发了相同的异常。

方法一

private final String serverUri = "tcp://95.177.135.232:9001";

private void mqqtConnectAndroidClient() {
    String clientId = "clientID-" + MqttClient.generateClientId();
    mqttAndroidClient = new MqttAndroidClient(getMainActivity(), serverUri, clientId);
    MqttConnectOptions mqttConnectOptions = new MqttConnectOptions();
    mqttConnectOptions.setKeepAliveInterval(60);
    mqttConnectOptions.setCleanSession(true);
    mqttConnectOptions.setMqttVersion(MqttConnectOptions.MQTT_VERSION_3_1_1);
    try {
        mqttAndroidClient.connect(mqttConnectOptions, null, new IMqttActionListener() {
            @Override
            public void onSuccess(IMqttToken asyncActionToken) {
                subscribeToTopic();
            }

            @Override
            public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                AppLog.Error("Failed to connect to: " + serverUri);
                exception.printStackTrace();
            }
        });
    } catch (MqttException e) {
        e.printStackTrace();
    }
}

方法二

private final String serverUri = "tcp://95.177.135.232:9001";

private void methodTwo() {
    try {
        MqttDefaultFilePersistence mdfp = new MqttDefaultFilePersistence(MQTT_DIR);
        mqttClient = new MqttClient(serverUri, "1", mdfp);
        MqttConnectOptions options = new MqttConnectOptions();
        options.setMqttVersion(MqttConnectOptions.MQTT_VERSION_3_1_1);
        options.setKeepAliveInterval(60);
        options.setAutomaticReconnect(true);
        options.setCleanSession(true);
        mqttClient.connect(options);
        mqttClient.subscribe("#");
        mqttClient.setCallback(new MqttCallback() {

            @Override
            public void connectionLost(Throwable arg0) {
                AppLog.Error("Connection lost");
                try {
                    mqttClient.connect();
                } catch (MqttException e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void deliveryComplete(IMqttDeliveryToken arg0) {
                AppLog.Error("deliveryComplete");
            }

            @Override
            public void messageArrived(String arg0, MqttMessage arg1) throws Exception {
                AppLog.Error("messageArrived");
                AppLog.Error(arg1.toString());
            }
        });
    } catch (MqttException e) {
        AppLog.Error("Main Exception");
        e.printStackTrace();
    }
}

订阅方式

public void subscribeToTopic() {
    try {
        String subscriptionTopic = "#";
        mqttAndroidClient.subscribe(subscriptionTopic, 0, null, new IMqttActionListener() {
            @Override
            public void onSuccess(IMqttToken asyncActionToken) {
                AppLog.Error("Subscribed!");
            }
            @Override
            public void onFailure(IMqttToken asyncActionToken, Throwable exception) {
                AppLog.Error("Failed to subscribe");
            }
        });
    } catch (MqttException ex) {
        System.err.println("Exception whilst subscribing");
        ex.printStackTrace();
    }
}

如果我在 HiveMQ 尝试相同的服务器 URI，它在正确连接的情况下工作得很好，订阅也给我结果。我正在使用以下两个库：

compile 'org.eclipse.paho:org.eclipse.paho.client.mqttv3:1.1.0' compile 'org.eclipse.paho:org.eclipse.paho.android.service:1.0.2'

我尝试了一些 SO 答案，例如 One, , Three, Four and ，但其中 none 对我有用。

如有任何帮助，我们将不胜感激。提前致谢！

Answer 1

您正在使用端口 9001，并且 HiveMQ Link 指向 MQTT over Websockets 客户端。

您正在指定一个以 tcp:// 开头的连接 URI，这将向服务发出信号，表明它应该使用本机 MQTT 而非 Websockets 上的 MQTT 进行连接。

如 bug 实现 Websocket 支持的报告中所述，您需要使用 ws:// 启动连接 URI，让客户端代码知道使用 Websockets。

Answer 2

我已解决问题，请在此处查看更多详细信息 https://github.com/eclipse/paho.mqtt.java/issues/207

很有趣，但即使在生成唯一客户端 ID 时我们也会看到这一点。多台机器上有多个客户端，所以我猜有可能是多台机器生成 clientID，但对于重复的 clientIds 来说，精确到纳秒级的可能性很小。

连接丢失 (32109) - java.io.EOFException (MqttAndroidClient)

Connection lost (32109) - java.io.EOFException (MqttAndroidClient)

java

android

mqtt

paho