RabbitMQ入门学习系列(五) Exchange的Direct类型

快速阅读

利用Exchange的Direct类型，实现对队列的过滤，消费者启动以后，输入相应的key值，攻取该key值对应的在队列中的消息 。

从一节知道Exchange有四种类型

Direct,Topic,headers,fanout

前面我们说了fanout类型，可以把消息发送给所有的消费者，

在用Fanout类型的时候，我们绑定的时候是没有指定Routing key的【空值】

 channel.BasicPublish(exchange: "logs",
                                         routingKey: "",
                                         basicProperties: null,
                                         body: body);

这次我们说一下Direct类型

Exchange的Direct类型将与队列中的routing key进行精确的匹配。

生产者代码

1. 创建连接和信道
2. 声明交换器名字和指定类型为direct
3. 发送routingkey=rk1 和rk2的消息各五次

static void Main(string[] args)
{
    var factory = new ConnectionFactory() { HostName = "localhost" };
    using (var connection = factory.CreateConnection())
        using (var channel = connection.CreateModel())
    {
        channel.ExchangeDeclare(exchange: "directType1", type: "direct");
        for (var i = 0; i < 5; i++)
        {
            string message = "Hello World!this rk1 message " + i;
            var body = Encoding.UTF8.GetBytes(message);
            var properties = channel.CreateBasicProperties();
            properties.Persistent = true;

            channel.BasicPublish(exchange: "directType1",
                                 routingKey: "rk1",
                                 basicProperties: null,
                                 body: body);

            Console.WriteLine(" [x] Sent {0},id={1}", message,i);
            Thread.Sleep(1000);
        }

        for (var i = 0; i < 5; i++)
        {
            string message = "Hello World!this rk2 message " + i;
            var body = Encoding.UTF8.GetBytes(message);
            var properties = channel.CreateBasicProperties();
            properties.Persistent = true;

            channel.BasicPublish(exchange: "directType1",
                                 routingKey: "rk2",
                                 basicProperties: null,
                                 body: body);

            Console.WriteLine(" [x] Sent {0},id={1}", message, i);
            Thread.Sleep(1000);
        }

    }

    Console.WriteLine(" Press [enter] to exit.");
    Console.ReadLine();
} 

消费者代码

1. 输入要查看的消息类型，支持rk1 和rk2
2. 创建连接和信道
3. 声明交换器名字和指定类型为direct
4. 指定队列名称，并且把routingkey的值赋值给控制台手动需要输入的rk1或者rk2
5. 接收消息并回馈，和fanout类型一样的代码了。

static void Main(string[] args)
{
    bool flag = true;
    string level = "";
    while (flag)
    {
        Console.WriteLine("请选择要查看的消息类型");
        level = Console.ReadLine();
        if (level == "rk1" || level == "rk2" )
            flag = false;
        else
            Console.Write("仅支持rk1与rk2");
    }

    var factory = new ConnectionFactory() { HostName = "localhost" };
    using (var connection = factory.CreateConnection())
    {
        using (var channel = connection.CreateModel())
        {
            channel.ExchangeDeclare(exchange: "directType1", type: "direct");
            var queueName = channel.QueueDeclare().QueueName;
            channel.QueueBind(queue: queueName, exchange: "directType1", routingKey: level);
            //以下是区别生产者的
            var consumer = new EventingBasicConsumer(channel);
            consumer.Received += (sender, e) =>
            {
                var body = e.Body;
                var message = Encoding.UTF8.GetString(body);
                var rk = e.RoutingKey;
                Console.WriteLine("Received {0},routingKey:{1}", message, rk);
                Thread.Sleep(3000);//模拟耗时任务 ，
                Console.WriteLine("Received over");
                channel.BasicAck(deliveryTag: e.DeliveryTag, multiple: false);
            };
            channel.BasicConsume(queue: queueName, autoAck: false, consumer: consumer);
            Console.WriteLine("");
            Console.ReadLine();
        }

    }

查看结果

我们看到生产者分别生产了五条rk1和五条rk2的消息

消费者1输入只查看rk1的消息，成功获得了rk1的消息

同样的

消费者2输入只查看rk2的消息，成功获得了rk2的消息

要注意的是先把先消费者启动起来