RabbitMQ (七) 订阅者模式之主题模式 ( topic )

主题模式和路由模式很像

路由模式是精确匹配

主题模式是模糊匹配

 

 

依然先通过管理后台添加一个交换机.

生产者

    public class Producer
    {

        private const string ExchangeName = "test_exchange_topic";

        public static void Send()
        {
            //获取一个连接
            IConnection connection = ConnectionHelper.GetConnection();

            //从连接中获取一个通道
            IModel channel = connection.CreateModel();

            //声明交换机
            //channel.ExchangeDeclare(ExchangeName, "topic", false, false, null);

            //每次只向消费者发送一条消息,消费者使用后,手动确认后,才会发送另外一条
            channel.BasicQos(0, 1, false);
            
            string msg = "hello world ";

            //发送消息,只发送到路由键为"product.delete" 或者 "product.#"的队列.
            //# 匹配一个或多个
            //* 匹配一个
            //上限为 255 个字节
            channel.BasicPublish(ExchangeName, "product.delete", null, Encoding.Default.GetBytes(msg));
            Console.WriteLine($"send {msg}");

            channel.Close();
            connection.Close();
        }
    }

 

消费者1

    public class Consumer1
    {
        private const string QueueName = "test_exchange1_queue";
        private const string ExchangeName = "test_exchange_topic";

        public static void Receive()
        {
            //获取连接
            RabbitMQ.Client.IConnection connection = ConnectionHelper.GetConnection();

            //创建通道
            RabbitMQ.Client.IModel channel = connection.CreateModel();

            //声明队列
            channel.QueueDeclare(QueueName, false, false, false, null);

            //将队列绑定到交换机上
            channel.QueueBind(QueueName, ExchangeName, "product.add", null);
            channel.QueueBind(QueueName, ExchangeName, "product.update", null);
            EventingBasicConsumer consumer = new EventingBasicConsumer(channel);

            //注册事件
            consumer.Received += (s, e) =>
            {
                byte[] bytes = e.Body;
                string str = Encoding.Default.GetString(bytes);
                Console.WriteLine("consumer1 : " + str);
                channel.BasicAck(e.DeliveryTag, false);//手动应答
            };

            //监听队列
            //bool autoAck = true;//自动确认,一旦mq将消息分发给了消费者,就会从内存中删除该消息
            bool autoAck = false;//手动应答.
            channel.BasicConsume(QueueName, autoAck, "", false, false, null, consumer);
        }
    }

 

消费者2

    public class Consumer2
    {
        private const string QueueName = "test_exchange2_queue";
        private const string ExchangeName = "test_exchange_topic";
        public static void Receive()
        {
            //获取连接
            RabbitMQ.Client.IConnection connection = ConnectionHelper.GetConnection();

            //创建通道
            RabbitMQ.Client.IModel channel = connection.CreateModel();

            //声明队列
            channel.QueueDeclare(QueueName, false, false, false, null);
            
            //将队列绑定到交换机上
            channel.QueueBind(QueueName, ExchangeName, "product.#", null);         //添加消费者
            EventingBasicConsumer consumer = new EventingBasicConsumer(channel);

            //注册事件
            consumer.Received += (s, e) =>
            {
                byte[] bytes = e.Body;
                string str = Encoding.Default.GetString(bytes);
                Console.WriteLine("         consumer2 : " + str);
                channel.BasicAck(e.DeliveryTag, false);//手动应答
            };

            //监听队列
            //bool autoAck = true;//自动确认,一旦mq将消息分发给了消费者,就会从内存中删除该消息
            bool autoAck = false;//手动应答.
            channel.BasicConsume(QueueName, autoAck, "", false, false, null, consumer);
        }
    }

 

运行结果:

 

 

由于消费者1的路由键只有 "product.add" 和 "product.update" ,不包含"product.delete",

而消费者2的路由键是"product.#",可以模糊匹配上"product.delete",

所以交换机只会把消息转发到消费者2声明的队列中.