mqtt 服务器搭建以及模拟相关的订阅发布测试（一）

1、搭建JAVA开发环境：JDK、JRE 环境搭建参考：https://www.cnblogs.com/smivico/p/6256313.html

2、网上下载apache，我这里用的是apache-apollo-1.7.1-windows，下载链接：http://activemq.apache.org/apollo/download.html

3、解压下载的apache：命令行 win+r 进入：D:\m_software\apache-apollo-1.7.1-windows-distro\apache-apollo-1.7.1\bin文件夹中，作如下操作：

输入：apollo.cmd create test 创建虚拟test服务器主机，在该文件夹下会生成一个test目录

4、进入 D:\m_software\apache-apollo-1.7.1-windows-distro\apache-apollo-1.7.1\bin\test\bin文件，开启服务器。

 

5、进入test目录下etc文件夹中，找到apollo.xml

打开浏览器：输入http://127.0.0.1:61680,任意一个都可以，即可进入管理的web界面，账户：admin ，密码：password。

6、测试连接，打开mqtt用户客户端，如下图所示：

7、查看服务器连接状态，如下图所示，已经连接上一个客户端：

8、测试一个订阅与发布：重新打开一个客户端作为管理客户端，负责发布：

此时，服务器显示有两个用户连接上了：

发布信息：

9、客户端实现

using MQTTnet;
using MQTTnet.Core;
using MQTTnet.Core.Client;
using MQTTnet.Core.Packets;
using MQTTnet.Core.Protocol;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace mqtt_client
{
    public partial class Form1 : Form
    {
        private MqttClient mqttClient = null;
        public Form1()
        {
            InitializeComponent();
            Task.Run(async () => { await ConnectMqttServerAsync(); });
        }
        private async Task ConnectMqttServerAsync()
        {
            if (mqttClient == null)
            {
                mqttClient = new MqttClientFactory().CreateMqttClient() as MqttClient;
                mqttClient.ApplicationMessageReceived += MqttClient_ApplicationMessageReceived;
                mqttClient.Connected += MqttClient_Connected;
                mqttClient.Disconnected += MqttClient_Disconnected;
            }

            try
            {
                var options = new MqttClientTcpOptions
                {
                    Server = "127.0.0.1",
                    Port=61613,
                    ClientId = Guid.NewGuid().ToString(),
                    UserName = "admin",
                    Password = "password",
                    CleanSession = true
                };

                await mqttClient.ConnectAsync(options);
            }
            catch (Exception ex)
            {
                Invoke((new Action(() =>
                {
                    textBox2.AppendText($"连接到MQTT服务器失败！" + Environment.NewLine + ex.Message + Environment.NewLine);
                })));
            }
        }
        private void MqttClient_Connected(object sender, EventArgs e)
        {
            Invoke((new Action(() =>
            {
                textBox2.AppendText("已连接到MQTT服务器！" + Environment.NewLine);
            })));
        }

        private void MqttClient_Disconnected(object sender, EventArgs e)
        {
            Invoke((new Action(() =>
            {
                textBox2.AppendText("已断开MQTT连接！" + Environment.NewLine);
            })));
        }

        private void MqttClient_ApplicationMessageReceived(object sender, MqttApplicationMessageReceivedEventArgs e)
        {
            Invoke((new Action(() =>
            {
                textBox2.AppendText($">> {Encoding.UTF8.GetString(e.ApplicationMessage.Payload)}{Environment.NewLine}");
            })));
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string topic = textBox1.Text.Trim();

            if (string.IsNullOrEmpty(topic))
            {
                MessageBox.Show("订阅主题不能为空！");
                return;
            }

            if (!mqttClient.IsConnected)
            {
                MessageBox.Show("MQTT客户端尚未连接！");
                return;
            }

            mqttClient.SubscribeAsync(new List {
                new TopicFilter(topic, MqttQualityOfServiceLevel.AtMostOnce)
            });

            textBox2.AppendText($"已订阅[{topic}]主题" + Environment.NewLine);
            textBox1.Enabled = false;
            button1.Enabled = false;

        }

        private void button2_Click(object sender, EventArgs e)
        {
            string topic = textBox4.Text.Trim();

            if (string.IsNullOrEmpty(topic))
            {
                MessageBox.Show("发布主题不能为空！");
                return;
            }

            string inputString = textBox3.Text.Trim();
            var appMsg = new MqttApplicationMessage(topic, Encoding.UTF8.GetBytes(inputString), MqttQualityOfServiceLevel.AtMostOnce, false);
            mqttClient.PublishAsync(appMsg);

        }

        private void Form1_Load(object sender, EventArgs e)
        {
            Sunisoft.IrisSkin.SkinEngine skin = new Sunisoft.IrisSkin.SkinEngine
            {
                SkinFile = @"./RealOne.ssk"
            };
        }
    }
}