Re: [paho-dev] how to use the new mqttPresistence, Qos and the acknowled

["James Sutton1" <james.sutton@xxxxxxxxxx>]

Hi Peiyuan,

 

There is an example project here: https://github.com/IBMJames/EclipsePahoMavenExample that shows how to publish a message. It uses QoS and MemoryPersistence.

 

In the example, if the MQTT Broker is not contactable then an MqttException will be thrown.

 

Console output when working:

 

paho/EclipsePahoMavenExample [ java -cp target/my-app-1.0-SNAPSHOT-jar-with-dependencies.jar org.eclipse.paho.App                          master * ] 9:53 AM
Connecting to broker: tcp://iot.eclipse.org:1883
Connected
Publishing message: Message from MqttPublishSample
Message published
Disconnected

 

 

When the broker cannot be contacted:

 

paho/EclipsePahoMavenExample [ java -cp target/my-app-1.0-SNAPSHOT-jar-with-dependencies.jar org.eclipse.paho.App                          master * ] 9:53 AM
Connecting to broker: tcp://iot.ceclipse.org:1883
reason 32103
msg Unable to connect to server
loc Unable to connect to server
cause java.net.ConnectException: Connection refused
excep Unable to connect to server (32103) - java.net.ConnectException: Connection refused
Unable to connect to server (32103) - java.net.ConnectException: Connection refused
    at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:79)
    at org.eclipse.paho.client.mqttv3.internal.ClientComms$ConnectBG.run(ClientComms.java:619)
    at java.lang.Thread.run(Thread.java:781)
Caused by: java.net.ConnectException: Connection refused
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:358)
    at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:219)
    at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:201)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.net.Socket.connect(Socket.java:616)
    at org.eclipse.paho.client.mqttv3.internal.TCPNetworkModule.start(TCPNetworkModule.java:70)
    ... 2 more

 

 

Kind regards,

 

James Sutton
Software Engineer - IoT Foundation - MQTT Open Source Projects
Technical Trojan - Wimbledon Project

Phone: 01962 815438 | Extension: x372454 E-mail: james.sutton@xxxxxxxxxx Personal Website: www.jsutton.co.uk Find me on:	Hursley Park Hursley, SO212JN United Kingdom

 

IBM United Kingdom Limited Registered in England and Wales with number 741598 Registered office: PO Box 41, North Harbour, Portsmouth, Hants. PO6 3AU

 

 

----- Original message -----
From: fang peiyuan <fang_peiyuan@xxxxxxxxx>
Sent by: paho-dev-bounces@xxxxxxxxxxx
To: "paho-dev@xxxxxxxxxxx" <paho-dev@xxxxxxxxxxx>
Cc:
Subject: [paho-dev] how to use the new mqttPresistence, Qos and the acknowledge from the MQTT broker
Date: Mon, Oct 19, 2015 7:34 AM
 

hi my name is peiyuan, currenly i am able to write a simple publisher and subscriber using java code and eclipse paho client thank to James.  Now i would like to go into QoS service and new MqttPresistence . So is there any tutorial or sample i can learn from it. 

 

At the same time i had problem in my current mqttpublisher how to return the connack from the broker server that i had connect to it? Because i want to know let say i forget to turn on my mosquitto server and hence i am not able to connect but currently even if i did not turn on my server, my client is still not a null and it till show is connected after i went through the debug mode 

 

my current code 

 

Mqttclient client = new Mqttclient (TCPaddress, ClientID, new Memorypresistence)

 

if (client != null)

{

    client .connect;

 

    if (!client.isconnected)

    {

        client.publish("topic", new MqttMessage("Message".getbytes));

}

 

thank you 

peiyuan 

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