臻识车牌识别配制MQTT通讯，解析车号

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在物联网项目中，我们的软件与车牌识别通讯，通常使用MQTT通讯更简单。

MQTT配制

测试工具

C# MqttHelper

using MQTTnet; using MQTTnet.Client; using MQTTnet.Protocol; using System; using System.Collections.Generic; using YUTU.DAL.Common; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Forms; using YUTU.BLL.Global; using System.Threading; namespace YUTU.BLL.Common.ClientMidle { public class MqttHelper { public IMqttClient _mqttClient; string serverIP, serverPort, user, pwd; ​ public MqttHelper(string ipAddr, string port, string userName, string userPwd) { serverIP = ipAddr; serverPort = port; user = userName; pwd = userPwd; } public bool blconntion = false; MqttClientOptions options = null; public Action<string> GetActionSubscribe; public async void ConntionServer() //async { try { LogMessage("serverIP[" + serverIP + "]serverPort[" + serverPort + "]user[" + user + "]pwd[" + pwd + "]"); options = new MqttClientOptions() { ClientId = Guid.NewGuid().ToString("D") }; options.ChannelOptions = new MqttClientTcpOptions() { Server = serverIP, Port = Convert.ToInt32(serverPort) }; options.Credentials = new MqttClientCredentials() { Username = user, Password = pwd }; options.CleanSession = true; options.KeepAlivePeriod = TimeSpan.FromSeconds(100.5); options.KeepAliveSendInterval = TimeSpan.FromSeconds(20000); ​ if (null != _mqttClient) { await _mqttClient.DisconnectAsync();//await _mqttClient = null; } _mqttClient = new MqttFactory().CreateMqttClient(); ​ _mqttClient.ApplicationMessageReceived += (sender, args) => { GetActionSubscribe?.Invoke(Encoding.UTF8.GetString(args.ApplicationMessage.Payload)); //ActionSubscribe?.Invoke(Encoding.UTF8.GetString(args.ApplicationMessage.Payload)); LogMessage(#34;ApplicationMessageReceived--ClientID:{args.ClientId} | TOPIC:{args.ApplicationMessage.Topic} | Payload:{Encoding.UTF8.GetString(args.ApplicationMessage.Payload)} | QoS:{args.ApplicationMessage.QualityOfServiceLevel} | Retain:{args.ApplicationMessage.Retain}"); ​ }; ​ _mqttClient.Connected += (sender, args) => { LogMessage(#34;Connected--Client is Connected: IsSessionPresent:{args.IsSessionPresent}"); }; ​ _mqttClient.Disconnected += (sender, args) => { LogMessage(#34;Client is DisConnected ClientWasConnected:{args.ClientWasConnected}"); }; ​ await _mqttClient.ConnectAsync(options);//await } catch (Exception ex) { LogMessage("ConntionServer异常:" + ex.Message); } } ​ public async void DisConntionServer() { try { LogMessage("开始执行DisConntionServer"); if (null != _mqttClient && _mqttClient.IsConnected) { await _mqttClient.DisconnectAsync(); _mqttClient.Dispose(); _mqttClient = null; } LogMessage("执行DisConntionServer成功..."); } catch (Exception ex) { LogMessage("DisConntionServer异常:" + ex.Message); } } ​ public async void HeartConntionServer() { try { LogMessage("开始执行HeartConntionServer"); if (null != _mqttClient && options != null) { await _mqttClient.ConnectAsync(options); } LogMessage("执行HeartConntionServer成功..."); } catch (Exception ex) { LogMessage("HeartConntionServer异常:" + ex.Message); } } ​ public void SendMessage(string Topic, string Payload) { try { LogMessage("SendMessage---Topic[" + Topic + "]Payload[" + Payload + "]"); Task.Factory.StartNew(async () => { var msg = new MqttApplicationMessage() { Topic = Topic, Payload = Encoding.UTF8.GetBytes(Payload), ​ QualityOfServiceLevel = (MqttQualityOfServiceLevel) Enum.Parse(typeof(MqttQualityOfServiceLevel), "1"),//Level Retain = false }; ​ if (null != _mqttClient) { await _mqttClient.PublishAsync(msg); } else { LogMessage("SendMessage_mqttClient为null"); } LogMessage("SendMessage成功:" + Payload); }); ​ } catch (Exception ex) { LogMessage("SendMessage异常:" + ex.Message); } } ​ public async void SubscribeAsync(string Topic) { try { LogMessage("SubscribeAsync---Topic[" + Topic + "]"); if (_mqttClient == null) return; ​ Thread.Sleep(1000); await _mqttClient.SubscribeAsync( new List<TopicFilter> { new TopicFilter( Topic, (MqttQualityOfServiceLevel) System.Enum.Parse(typeof (MqttQualityOfServiceLevel), "1")) }); } catch (Exception ex) { LogMessage("SubscribeAsync异常:" + ex.Message); } } } } ​

订阅消息

private MqttHelper _mqttHelper = null; private static string mqttIP = ConfigurationManager.AppSettings["MqttIP"]; private static string mqttTCPPort = ConfigurationManager.AppSettings["MqttTCPPort"]; private static string mqttUser = ConfigurationManager.AppSettings["MqttUser"]; private static string mqttPwd = ConfigurationManager.AppSettings["MqttPwd"]; ​ public void Init() { try { //MQTT参数配置 string ipAddr = mqttIP; string port = mqttTCPPort; string userName = mqttUser; string userPwd = mqttPwd; //mqtt消息队列 _mqttHelper = new MqttHelper(ipAddr, port, userName, userPwd); ​ } catch (Exception e) { throw new Exception(#34;Init异常，{e.Message}"); } } ​ public void TurnOn() { try { if (_mqttHelper == null) throw new Exception("Init异常"); _mqttHelper.ConntionServer(); ​ //接收订阅消息 _mqttHelper.GetActionSubscribe = (obj) => { var msgObj = JsonConvert.DeserializeObject<MsgModel>(obj); if (msgObj != null) { ReceiveMsgCallback?.Invoke(msgObj); } }; ​ //订阅消息 _mqttHelper.SubscribeAsync(#34;071c55ad-f1a5a757/device/message/up/ivs_result"); ​ //MQTT心跳 MessageListenerTimer = new System.Timers.Timer(); MessageListenerTimer.Elapsed += new ElapsedEventHandler(MessageListenerTimer_Elapsed); MessageListenerTimer.Enabled = true; } catch (Exception e) { throw new Exception(#34;TurnOn异常，{e.Message}"); } } ​ public void TurnOff() { try { MessageListenerTimer.Enabled = false; if (_mqttHelper != null) _mqttHelper.DisConntionServer(); } catch (Exception e) { throw new Exception(#34;TurnOff异常，{e.Message}"); } }

解析车号

var license = msgObj.payload.AlarmInfoPlate.result.PlateResult.license; // 解码车号 string base64License = System.Text.Encoding.UTF8.GetString(Convert.FromBase64String(license));