.NET中RabbitMQ的direct类型Exchange的使用

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Producter发送消息代码：

/// <summary>
        /// 连接配置
        /// </summary>
        private static readonly ConnectionFactory rabbitMqFactory = new ConnectionFactory(){
            HostName ="192.168.1.8",UserName="hao",Password="abc123",Port= 5672
        };
        /// <summary>
        /// 路由名称
        /// </summary>
        const string ExchangeName = "justin.exchange";

        //队列名称
        const string QueueName = "justin.queue";
        public static void DirectExchangeSendMsg()
        {
            using (IConnection conn = rabbitMqFactory.CreateConnection())
            {
                using (IModel channel = conn.CreateModel())
                {
                    channel.ExchangeDeclare(ExchangeName, "direct", durable: true, autoDelete: false, arguments: null);
                    channel.QueueDeclare(QueueName, durable: true, autoDelete: false, exclusive: false, arguments: null);
                    channel.QueueBind(QueueName, ExchangeName, routingKey: QueueName);

                    var props = channel.CreateBasicProperties();
                    props.Persistent = true;
                    string vadata = Console.ReadLine();
                    while (vadata != "exit")
                    {
                        var msgBody = Encoding.UTF8.GetBytes(vadata);
                        channel.BasicPublish(exchange: ExchangeName, routingKey: QueueName, basicProperties: props, body: msgBody);        
                        Console.WriteLine(string.Format("***发送时间:{0}，发送完成，输入exit退出消息发送",DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss")));
                        vadata = Console.ReadLine();
                    }                   
                }
            }
        }

Customer接收消息代码：

/// <summary>
        /// 连接配置
        /// </summary>
        private static readonly ConnectionFactory rabbitMqFactory = new ConnectionFactory() {
            HostName = "192.168.1.8", UserName = "hao", Password = "abc123", Port = 5672
        };
        /// <summary>
        /// 路由名称
        /// </summary>
        const string ExchangeName = "justin.exchange";

        //队列名称
        const string QueueName = "justin.queue";
        public static void DirectAcceptExchange()
        {
            using (IConnection conn = rabbitMqFactory.CreateConnection())
            {
                using (IModel channel = conn.CreateModel())
                {
                    channel.ExchangeDeclare(ExchangeName, "direct", durable: true, autoDelete: false, arguments: null);
                    channel.QueueDeclare(QueueName, durable: true, autoDelete: false, exclusive: false, arguments: null);
                    channel.QueueBind(QueueName, ExchangeName, routingKey: QueueName);
                    while (true)
                    { 
                        BasicGetResult msgResponse = channel.BasicGet(QueueName, noAck: true);
                        if (msgResponse != null)
                        {
                            var msgBody = Encoding.UTF8.GetString(msgResponse.Body);
                            Console.WriteLine(string.Format("***接收时间:{0}，消息内容：{1}", DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss"),msgBody));
                        }

                        //BasicGetResult msgResponse2 = channel.BasicGet(QueueName, noAck: false);

                        ////process message ...

                        //channel.BasicAck(msgResponse2.DeliveryTag, multiple: false);
                        System.Threading.Thread.Sleep(TimeSpan.FromSeconds(1));
                    }
                }
            }
        }

但是这种处理速度较慢，因为循环线程等待。高效的接收消息的方式可以使用EventingBasicConsumer进行消息接收处理，修改代码内容如下：

public static void DirectAcceptExchangeEvent()
        {
            using (IConnection conn = rabbitMqFactory.CreateConnection())
            {
                using (IModel channel = conn.CreateModel())
                {
                    //channel.ExchangeDeclare(ExchangeName, "direct", durable: true, autoDelete: false, arguments: null);
                    channel.QueueDeclare(QueueName, durable: true, autoDelete: false, exclusive: false, arguments: null);
                    //channel.QueueBind(QueueName, ExchangeName, routingKey: QueueName);
                    var consumer = new EventingBasicConsumer(channel);
                    consumer.Received += (model, ea) =>
                    {                        
                        var msgBody = Encoding.UTF8.GetString(ea.Body);
                        Console.WriteLine(string.Format("***接收时间:{0}，消息内容：{1}", DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss"), msgBody));
                    };
                    channel.BasicConsume(QueueName, noAck: true, consumer: consumer);

                    //已过时用EventingBasicConsumer代替
                    //var consumer2 = new QueueingBasicConsumer(channel);
                    //channel.BasicConsume(QueueName, noAck: true, consumer: consumer);
                    //var msgResponse = consumer2.Queue.Dequeue(); //blocking
                    //var msgBody2 = Encoding.UTF8.GetString(msgResponse.Body);

                    Console.WriteLine("按任意值，退出程序");
                    Console.ReadKey();
                }
            }
        }

但是有些时候，消费者同一时间没有能力处理太多的业务，导致分配过来的队列消息不能及时处理完成，这个时候，我们可以设置BasicQos属性，告诉Broker同一时间将未处理完成的消息分配其他消费者，所以接收消息的地方需要略做修改，代码如下：

public static void DirectAcceptExchangeTask()
{
    using (IConnection conn = rabbitMqFactory.CreateConnection())
    {
        using (IModel channel = conn.CreateModel())
        {
            //channel.ExchangeDeclare(ExchangeName, "direct", durable: true, autoDelete: false, arguments: null);
            channel.QueueDeclare(QueueName, durable: true, autoDelete: false, exclusive: false, arguments: null);
            channel.BasicQos(prefetchSize: 0, prefetchCount: 1, global: false);//告诉broker同一时间只处理一个消息
            //channel.QueueBind(QueueName, ExchangeName, routingKey: QueueName);
            var consumer = new EventingBasicConsumer(channel);
            consumer.Received += (model, ea) =>
            {
                var msgBody = Encoding.UTF8.GetString(ea.Body);
                Console.WriteLine(string.Format("***接收时间:{0}，消息内容：{1}", DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss"), msgBody));
                int dots = msgBody.Split('.').Length - 1;
                System.Threading.Thread.Sleep(dots * 1000);
                Console.WriteLine(" [x] Done");
                //处理完成，告诉Broker可以服务端可以删除消息，分配新的消息过来
                channel.BasicAck(deliveryTag: ea.DeliveryTag, multiple: false);
            };
            //noAck设置false,告诉broker，发送消息之后，消息暂时不要删除，等消费者处理完成再说
            channel.BasicConsume(QueueName, noAck: false, consumer: consumer);

            Console.WriteLine("按任意值，退出程序");
            Console.ReadKey();
        }
    }
}