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我下载的是windows版

安装

参考
http://emqtt.com/docs/install.html

将下载的压缩包解压，我解压到了D盘

命令行窗口，cd到程序目录

控制台模式启动:

.\bin\emqttd console

报错如下

无法启动此程序，因为计算机中丢失 MSVCR120.dll。尝试重新安装该程序以解决次问题。

找一个MSVCR120.dll文件，可以去网上下载，也可以在自己电脑上找

HBuilder下有
mqttfx下也有
XMind下也有
IDEA下也有

我拷贝一个mqttfx下的到Windows\System32下

然后重新执行

.\bin\emqttd console

启动成功

登录

http://localhost:18083/

用户名为admin密码为public

登录上去就可以看服务器的运行状态了

测试

<dependency>  
    <groupId>org.eclipse.paho</groupId>  
    <artifactId>org.eclipse.paho.client.mqttv3</artifactId>  
    <version>1.0.2</version>  
</dependency>

package com.mymqtt.myemqtt;

import java.util.Scanner;

import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;
import org.eclipse.paho.client.mqttv3.MqttMessage;

public class Server {

public static void main(String\[\] args) throws Exception {  
    String host = "tcp://127.0.0.1:1883";  
    String topic = "hello";  
    String clientId = "server";// clientId不能重复  
    MqttConnectOptions options = new MqttConnectOptions();  
    options.setCleanSession(true);

    MqttClient client = new MqttClient(host, clientId);  
    client.connect(options);

    MqttMessage message = new MqttMessage();

    @SuppressWarnings("resource")  
    Scanner scanner = new Scanner(System.in);  
    System.out.println("请输入要发送的内容：");  
    while (true) {  
        String line = scanner.nextLine();  
        message.setPayload(line.getBytes());  
        client.publish(topic, message);  
    }

}  

}

package com.mymqtt.myemqtt;

import org.eclipse.paho.client.mqttv3.MqttClient;
import org.eclipse.paho.client.mqttv3.MqttConnectOptions;

public class Client {

public static void main(String\[\] args) throws Exception {

    String host = "tcp://127.0.0.1:1883";  
    String topic = "hello";  
    String clientId = "12345";// clientId不能重复  
    // 1.设置mqtt连接属性  
    MqttConnectOptions options = new MqttConnectOptions();  
    options.setCleanSession(true);  
    // 2.实例化mqtt客户端  
    MqttClient client = new MqttClient(host, clientId);  
    // 3.连接  
    client.connect(options);

    client.setCallback(new PushCallback());  
    while (true) {  
        client.subscribe(topic, 2);  
    }  
    // client.disconnect();  
}  

}

package com.mymqtt.myemqtt;

import java.util.Date;

import org.eclipse.paho.client.mqttv3.IMqttDeliveryToken;
import org.eclipse.paho.client.mqttv3.MqttCallback;
import org.eclipse.paho.client.mqttv3.MqttMessage;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class PushCallback implements MqttCallback {
    private final Logger logger = LoggerFactory.getLogger(this.getClass());

    public void connectionLost(Throwable cause) {
        // 连接丢失后，一般在这里面进行重连
        System.out.println("连接断开，可以做重连");
        logger.info("掉线时间:{}", new Date());
    }

    public void deliveryComplete(IMqttDeliveryToken token) {
        System.out.println("deliveryComplete---------" + token.isComplete());
    }

    public void messageArrived(String topic, MqttMessage message) throws Exception {
        // subscribe后得到的消息会执行到这里面
        // System.out.println(message);
        System.out.println("接收消息主题 : " + topic);
        System.out.println("接收消息Qos : " + message.getQos());
        System.out.println("接收消息内容 : " + new String(message.getPayload()));
    }

}

两个连接

参考文献

http://emqtt.com/

百度开放云物接入IoT–Java客户端

--------------------- 本文来自 GW_Cheng 的CSDN 博客 ，全文地址请点击：https://blog.csdn.net/frankcheng5143/article/details/52045501?utm_source=copy