物联网消息队列协议MQTT

时间：2022-01-10 15:22:54

简介
Mqtt是一个物联网消息传输协议

mosquitto是mqtt协议的一个开源实现，http://mosquitto.org/

paho是mqtt协议的客户端实现，这里主要用paho的mqtt java客户端jar包。

http://wiki.eclipse.org/Paho

只需要在pom.xml中增加：

<dependency>

　　<groupId>org.eclipse.paho</groupId>

　　<artifactId>org.eclipse.paho.client.mqttv3</artifactId>

　　<version>1.0.2</version>

</dependency>

mosquitto可以理解为mutt协议的server端，可部署在linux及windows上

CentOS的安装过程：

参照官网文档，在yum的repo配置中增加：

[home_oojah_mqtt]

name=mqtt (CentOS_CentOS-)

type=rpm-md

baseurl=http://download.opensuse.org/repositories/home:/oojah:/mqtt/CentOS_CentOS-6/

gpgcheck=

gpgkey=http://download.opensuse.org/repositories/home:/oojah:/mqtt/CentOS_CentOS-6//repodata/repomd.xml.key

enabled=

mosquitto的配置文件项可参考：http://blog.csdn.net/shagoo/article/details/7910598

集群部署 参照http://www.cnblogs.com/yinyi521/p/6087215.html

然后执行：
yum install mosquitto
yum install mosquitto-client

启动mosquitto服务：

mosquitto -v

mqtt java客户端实例：

package com.haibran.mqtt_demo;

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.MqttMessage;

import org.eclipse.paho.client.mqttv3.persist.MemoryPersistence;

public class MqttPublicSample {

public static void main(String[] args) {

// TODO Auto-generated method stub

String topic = "sensor";

String content = "Message from MqttPublishSample";

int qos = 2;

String broker = "tcp://192.168.0.20:1883";

String clientId = "JavaSample";

MemoryPersistence persistence = new MemoryPersistence();

try {

MqttClient sampleClient = new MqttClient(broker, clientId, persistence);

MqttConnectOptions connOpts = new MqttConnectOptions();

connOpts.setCleanSession(true);

System.out.println("Connecting to broker: "+broker);

sampleClient.connect(connOpts);

System.out.println("Connected");

System.out.println("Publishing message: "+content);

MqttMessage message = new MqttMessage(content.getBytes());

message.setQos(qos);

sampleClient.publish(topic, message);

System.out.println("Message published");

sampleClient.disconnect();

System.out.println("Disconnected");

System.exit(0);

} catch(MqttException me) {

System.out.println("reason "+me.getReasonCode());

System.out.println("msg "+me.getMessage());

System.out.println("loc "+me.getLocalizedMessage());

System.out.println("cause "+me.getCause());

System.out.println("excep "+me);

me.printStackTrace();

}

}

}

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