路由模式（Routing）
有选择地（Routing key）接收消息，发送消息到交换机并且要指定路由key ，消费者将队列绑定到交换机时需要指定路由key，仅消费指定路由key的消息
Exchange不再把消息交给每一个绑定的队列，而是根据消息的RoutingKey进行判断，只有队列的RoutingKey与消息的RoutingKey完全一致，才会接收消息，路由模式使用的Exchange类型为Direct类型
应用场景： 如在商品库存中增加了1台iphone12，iphone12促销活动消费者指定routing key为iphone12，只有此促销活动会接收到消息，其它促销活动不关心也不会消费此routing key的消息
Demo 架构与订阅模式一样
生产者类WeatherDirect.cs
1 using System;
2 using System.Collections.Generic;
3 using System.Text;
4 using RabbitMQ.Client;
5 using RabbitMQ.Common;
6
7 namespace RabbitMQ.Producer.Producer
8 {
9 public class WeatherDirect
10 {
11 public static void SendWeather()
12 {
13 Dictionary<string, string> area = new Dictionary<string, string>();
14 area.Add("china.hunan.changsha.20211231", "中国湖南长沙20211231天气数据");
15 area.Add("china.hubei.wuhan.20211231", "中国湖北武汉20211231天气数据");
16 area.Add("china.hubei.xiangyang.20211231", "中国湖北襄阳20211231天气数据");
17 area.Add("us.cal.lsj.20211231", "美国加州洛杉矶20211231天气数据");
18
19 using (var connection = RabbitUtils.GetConnection().CreateConnection())
20 {
21 using (var channel = connection.CreateModel())
22 {
23 foreach (var item in area)
24 {
25 channel.BasicPublish(RabbitConstant.EXCHANGE_WEATHER_ROUTING, item.Key, null, Encoding.UTF8.GetBytes(item.Value));
26 }
27 Console.WriteLine("气象信息发送成功！");
28 Console.WriteLine("Press [Enter] to exit");
29 Console.ReadLine();
30 }
31 }
32 }
33 }
34 }
消费者1 WeatherDirect.cs
1 using RabbitMQ.Client;
2 using RabbitMQ.Client.Events;
3 using RabbitMQ.Common;
4 using System;
5 using System.Collections.Generic;
6 using System.Text;
7
8 namespace RabbitMQ.Consumer01.Consumer
9 {
10 public class WeatherDirect
11 {
12 public static void ReceiveWeatherInfo()
13 {
14 using (var connection = RabbitUtils.GetConnection().CreateConnection())
15 {
16 using (var channel = connection.CreateModel())
17 {
18 channel.ExchangeDeclare(RabbitConstant.EXCHANGE_WEATHER_ROUTING, ExchangeType.Direct);
19 channel.QueueDeclare(RabbitConstant.QUEUE_BAIDU, true, false, false, null);
20 /*
21 * QueueBind用于将队列与交换机绑定
22 * queue:队列名
23 * exchange:交换机名
24 * routingKey：路由key
25 */
26 channel.QueueBind(queue: RabbitConstant.QUEUE_BAIDU,
27 exchange: RabbitConstant.EXCHANGE_WEATHER_ROUTING,
28 routingKey: "china.hunan.changsha.20211231");
29 channel.QueueBind(queue: RabbitConstant.QUEUE_BAIDU,
30 exchange: RabbitConstant.EXCHANGE_WEATHER_ROUTING,
31 routingKey: "china.hubei.wuhan.20211231");
32 channel.BasicQos(0, 1, false);
33 var consumer = new EventingBasicConsumer(channel);
34
35 consumer.Received += (model, ea) =>
36 {
37 var message = Encoding.UTF8.GetString(ea.Body.ToArray());
38 Console.WriteLine($"百度收到的气象信息：{message}");
39 channel.BasicAck(ea.DeliveryTag, false);
40 };
41 channel.BasicConsume(queue: RabbitConstant.QUEUE_BAIDU,
42 autoAck: false,
43 consumer: consumer);
44 Console.WriteLine(" Press [enter] to exit.");
45 Console.ReadLine();
46 }
47 }
48 }
49 }
50 }
消费者2 WeatherDirect.cs
1 using System;
2 using System.Collections.Generic;
3 using System.Text;
4 using RabbitMQ.Client;
5 using RabbitMQ.Client.Events;
6 using RabbitMQ.Common;
7
8 namespace RabbitMQ.Consumer02.Consumer
9 {
10 public class WeatherDirect
11 {
12 public static void ReceiveWeatherInfo()
13 {
14 using (var connection = RabbitUtils.GetConnection().CreateConnection())
15 {
16 using (var channel = connection.CreateModel())
17 {
18 channel.ExchangeDeclare(RabbitConstant.EXCHANGE_WEATHER_ROUTING, ExchangeType.Direct);
19 channel.QueueDeclare(RabbitConstant.QUEUE_SINA, true, false, false, null);
20 /*
21 * QueueBind用于将队列与交换机绑定
22 * queue:队列名
23 * exchange:交换机名
24 * routingKey：路由key
25 */
26 channel.QueueBind(queue: RabbitConstant.QUEUE_SINA,
27 exchange: RabbitConstant.EXCHANGE_WEATHER_ROUTING,
28 routingKey: "china.hubei.xiangyang.20211231");
29 channel.QueueBind(queue: RabbitConstant.QUEUE_SINA,
30 exchange: RabbitConstant.EXCHANGE_WEATHER_ROUTING,
31 routingKey: "china.hubei.wuhan.20211231");
32 channel.QueueBind(queue: RabbitConstant.QUEUE_SINA,
33 exchange: RabbitConstant.EXCHANGE_WEATHER_ROUTING,
34 routingKey: "us.cal.lsj.20211231");
35 channel.BasicQos(0, 1, false);
36 var consumer = new EventingBasicConsumer(channel);
37
38 consumer.Received += (model, ea) =>
39 {
40 var message = Encoding.UTF8.GetString(ea.Body.ToArray());
41 Console.WriteLine($"新浪收到的气象信息：{message}");
42 channel.BasicAck(ea.DeliveryTag, false);
43 };
44 channel.BasicConsume(queue: RabbitConstant.QUEUE_SINA,
45 autoAck: false,
46 consumer: consumer);
47 Console.WriteLine(" Press [enter] to exit.");
48 Console.ReadLine();
49 }
50 }
51 }
52 }
53 }
执行结果
备注：若执行报错：'PRECONDITION_FAILED - inequivalent arg 'type' for exchange
原因：一旦创建了exchange, RabbitMQ是不允许对其改变的,不然会报错
解决方法：在web上Exchanges模块把之前的exchange删除。
参考连接：https://www.bilibili.com/video/BV1GU4y1w7Yq?p=8
https://mp.weixin.qq.com/s/QG3uXhhpkE_Uo6Me15mxdg
https://blog.csdn.net/adviceuser2014/article/details/102259145