前言
RabbitMq大家再熟悉不过，这篇文章主要整对rabbitmq学习后封装RabbitMQ.Client的一个分享。文章最后，我会把封装组件和demo奉上。
Rabbitmq的关键术语
1、绑定器(Binding)：根据路由规则绑定Queue和Exchange。
2、路由键(Routing Key)：Exchange根据关键字进行消息投递。
3、交换机（Exchange）：指定消息按照路由规则进入指定队列
4、消息队列（Queue）：消息的存储载体
5、生产者（Producer）：消息发布者。
6、消费者（Consumer）：消息接收者。
Rabbitmq的运作
从下图可以看出，发布者（Publisher）是把消息先发送到交换器（Exchange），再从交换器发送到指定队列（Queue），而先前已经声明交换器与队列绑定关系，最后消费者（Customer）通过订阅或者主动取指定队列消息进行消费。
那么刚刚提到的订阅和主动取可以理解成，推（被动），拉（主动）。
推，只要队列增加一条消息，就会通知空闲的消费者进行消费。（我不找你，就等你找我，观察者模式）
拉，不会通知消费者，而是由消费者主动轮循或者定时去取队列消息。（我需要才去找你）
使用场景我举个例子，假如有两套系统 订单系统和发货系统，从订单系统发起发货消息指令，为了及时发货，发货系统需要订阅队列，只要有指令就处理。
可是程序偶尔会出异常，例如网络或者DB超时了，把消息丢到失败队列，这个时候需要重发机制。但是我又不想while(IsPostSuccess == True)，因为只要出异常了，会在某个时间段内都会有异常，这样的重试是没意义的。
这个时候不需要及时的去处理消息，有个JOB定时或者每隔几分钟（失败次数*间隔分钟）去取失败队列消息，进行重发。
Publish（发布）的封装
步骤：初始化链接->声明交换器->声明队列->换机器与队列绑定->发布消息。注意的是，我将Model存到了ConcurrentDictionary里面，因为声明与绑定是非常耗时的，其次，往重复的队列发送消息是不需要重新初始化的。
1 ????????/// <summary> 2 ????????/// 交换器声明 3 ????????/// </summary> 4 ????????/// <param name="iModel"></param> 5 ????????/// <param name="exchange">交换器</param> 6 ????????/// <param name="type">交换器类型： 7 ????????/// 1、Direct Exchange – 处理路由键。需要将一个队列绑定到交换机上，要求该消息与一个特定的路由键完全 8 ????????/// 匹配。这是一个完整的匹配。如果一个队列绑定到该交换机上要求路由键 “dog”，则只有被标记为“dog”的 9 ????????/// 消息才被转发，不会转发dog.puppy，也不会转发dog.guard，只会转发dog10 ????????/// 2、Fanout Exchange – 不处理路由键。你只需要简单的将队列绑定到交换机上。一个发送到交换机的消息都11 ????????/// 会被转发到与该交换机绑定的所有队列上。很像子网广播，每台子网内的主机都获得了一份复制的消息。Fanout12 ????????/// 交换机转发消息是最快的。13 ????????/// 3、Topic Exchange – 将路由键和某模式进行匹配。此时队列需要绑定要一个模式上。符号“#”匹配一个或多14 ????????/// 个词，符号“*”匹配不多不少一个词。因此“audit.#”能够匹配到“audit.irs.corporate”，但是“audit.*”15 ????????/// 只会匹配到“audit.irs”。</param>16 ????????/// <param name="durable">持久化</param>17 ????????/// <param name="autoDelete">自动删除</param>18 ????????/// <param name="arguments">参数</param>19 ????????private static void ExchangeDeclare(IModel iModel, string exchange, string type = ExchangeType.Direct,20 ????????????bool durable = true,21 ????????????bool autoDelete = false, IDictionary<string, object> arguments = null)22 ????????{23 ????????????exchange = exchange.IsNullOrWhiteSpace() ? "" : exchange.Trim();24 ????????????iModel.ExchangeDeclare(exchange, type, durable, autoDelete, arguments);25 ????????}26 27 ????????/// <summary>28 ????????/// 队列声明29 ????????/// </summary>30 ????????/// <param name="channel"></param>31 ????????/// <param name="queue">队列</param>32 ????????/// <param name="durable">持久化</param>33 ????????/// <param name="exclusive">排他队列，如果一个队列被声明为排他队列，该队列仅对首次声明它的连接可见，34 ????????/// 并在连接断开时自动删除。这里需要注意三点：其一，排他队列是基于连接可见的，同一连接的不同信道是可35 ????????/// 以同时访问同一个连接创建的排他队列的。其二，“首次”，如果一个连接已经声明了一个排他队列，其他连36 ????????/// 接是不允许建立同名的排他队列的，这个与普通队列不同。其三，即使该队列是持久化的，一旦连接关闭或者37 ????????/// 客户端退出，该排他队列都会被自动删除的。这种队列适用于只限于一个客户端发送读取消息的应用场景。</param>38 ????????/// <param name="autoDelete">自动删除</param>39 ????????/// <param name="arguments">参数</param>40 ????????private static void QueueDeclare(IModel channel, string queue, bool durable = true, bool exclusive = false,41 ????????????bool autoDelete = false, IDictionary<string, object> arguments = null)42 ????????{43 ????????????queue = queue.IsNullOrWhiteSpace() ? "UndefinedQueueName" : queue.Trim();44 ????????????channel.QueueDeclare(queue, durable, exclusive, autoDelete, arguments);45 ????????}46 47 ????????/// <summary>48 ????????/// 获取Model49 ????????/// </summary>50 ????????/// <param name="exchange">交换机名称</param>51 ????????/// <param name="queue">队列名称</param>52 ????????/// <param name="routingKey"></param>53 ????????/// <param name="isProperties">是否持久化</param>54 ????????/// <returns></returns>55 ????????private static IModel GetModel(string exchange, string queue, string routingKey, bool isProperties = false)56 ????????{57 ????????????return ModelDic.GetOrAdd(queue, key =>58 ????????????{59 ????????????????var model = _conn.CreateModel();60 ????????????????ExchangeDeclare(model, exchange, ExchangeType.Fanout, isProperties);61 ????????????????QueueDeclare(model, queue, isProperties);62 ????????????????model.QueueBind(queue, exchange, routingKey);63 ????????????????ModelDic[queue] = model;64 ????????????????return model;65 ????????????});66 ????????}67 68 ????????/// <summary>69 ????????/// 发布消息70 ????????/// </summary>71 ????????/// <param name="routingKey">路由键</param>72 ????????/// <param name="body">队列信息</param>73 ????????/// <param name="exchange">交换机名称</param>74 ????????/// <param name="queue">队列名</param>75 ????????/// <param name="isProperties">是否持久化</param>76 ????????/// <returns></returns>77 ????????public void Publish(string exchange, string queue, string routingKey, string body, bool isProperties = false)78 ????????{79 ????????????var channel = GetModel(exchange, queue, routingKey, isProperties);80 81 ????????????try82 ????????????{83 ????????????????channel.BasicPublish(exchange, routingKey, null, body.SerializeUtf8());84 ????????????}85 ????????????catch (Exception ex)86 ????????????{87 ????????????????throw ex.GetInnestException();88 ????????????}89 ????????} ???????下次是本机测试的发布速度截图：
4.2W/S属于稳定速度，把反序列化（ToJson）会稍微快一些。
Subscribe（订阅）的封装
发布的时候是申明了交换器和队列并绑定，然而订阅的时候只需要声明队列就可。从下面代码能看到，捕获到异常的时候，会把消息送到自定义的“死信队列”里，由另外的JOB进行定时重发，因此，finally是应答成功的。
???????/// <summary> ???????/// 获取Model ???????/// </summary> ???????/// <param name="queue">队列名称</param> ???????/// <param name="isProperties"></param> ???????/// <returns></returns> ???????private static IModel GetModel(string queue, bool isProperties = false) ???????{ ???????????return ModelDic.GetOrAdd(queue, value => ????????????{ ????????????????var model = _conn.CreateModel(); ????????????????QueueDeclare(model, queue, isProperties); ????????????????//每次消费的消息数 ????????????????model.BasicQos(0, 1, false); ????????????????ModelDic[queue] = model; ????????????????return model; ????????????}); ???????} ???????????/// <summary> ???????/// 接收消息 ???????/// </summary> ???????/// <typeparam name="T"></typeparam> ???????/// <param name="queue">队列名称</param> ???????/// <param name="isProperties"></param> ???????/// <param name="handler">消费处理</param> ???????/// <param name="isDeadLetter"></param> ???????public void Subscribe<T>(string queue, bool isProperties, Action<T> handler, bool isDeadLetter) where T : class ???????{ ???????????//队列声明 ???????????var channel = GetModel(queue, isProperties); ???????????var consumer = new EventingBasicConsumer(channel); ???????????consumer.Received += (model, ea) => ???????????{ ???????????????var body = ea.Body; ???????????????var msgStr = body.DeserializeUtf8(); ???????????????var msg = msgStr.FromJson<T>(); ???????????????try ???????????????{ ???????????????????handler(msg); ???????????????} ???????????????catch (Exception ex) ???????????????{ ???????????????????ex.GetInnestException().WriteToFile("队列接收消息", "RabbitMq"); ???????????????????if (!isDeadLetter) ???????????????????????PublishToDead<DeadLetterQueue>(queue, msgStr, ex); ???????????????} ???????????????finally ???????????????{ ???????????????????channel.BasicAck(ea.DeliveryTag, false); ???????????????} ???????????}; ???????????channel.BasicConsume(queue, false, consumer); ???????} ???????下次是本机测试的发布速度截图：
快的时候有1.9K/S，慢的时候也有1.7K/S
Pull（拉）的封装
直接上代码：
???????/// <summary> ???????/// 获取消息 ???????/// </summary> ???????/// <typeparam name="T"></typeparam> ???????/// <param name="exchange"></param> ???????/// <param name="queue"></param> ???????/// <param name="routingKey"></param> ???????/// <param name="handler">消费处理</param> ???????private void Poll<T>(string exchange, string queue, string routingKey, Action<T> handler) where T : class ???????{ ???????????var channel = GetModel(exchange, queue, routingKey); ???????????var result = channel.BasicGet(queue, false); ???????????if (result.IsNull()) ???????????????return; ???????????var msg = result.Body.DeserializeUtf8().FromJson<T>(); ???????????try ???????????{ ???????????????handler(msg); ???????????} ???????????catch (Exception ex) ???????????{ ???????????????ex.GetInnestException().WriteToFile("队列接收消息", "RabbitMq"); ???????????} ???????????finally ???????????{ ???????????????channel.BasicAck(result.DeliveryTag, false); ???????????} ???????} ???快的时候有1.8K/s，稳定是1.5K/S
Rpc（远程调用）的封装
首先说明下，RabbitMq只是提供了这个RPC的功能，但是并不是真正的RPC，为什么这么说：
1、传统Rpc隐藏了调用细节，像调用本地方法一样传参、抛出异常
2、RabbitMq的Rpc是基于消息的，消费者消费后，通过新队列返回响应结果。
???????/// <summary> ???????/// RPC客户端 ???????/// </summary> ???????/// <param name="exchange"></param> ???????/// <param name="queue"></param> ???????/// <param name="routingKey"></param> ???????/// <param name="body"></param> ???????/// <param name="isProperties"></param> ???????/// <returns></returns> ???????public string RpcClient(string exchange, string queue, string routingKey, string body, bool isProperties = false) ???????{ ???????????var channel = GetModel(exchange, queue, routingKey, isProperties); ???????????var consumer = new QueueingBasicConsumer(channel); ???????????channel.BasicConsume(queue, true, consumer); ???????????try ???????????{ ???????????????var correlationId = Guid.NewGuid().ToString(); ???????????????var basicProperties = channel.CreateBasicProperties(); ???????????????basicProperties.ReplyTo = queue; ???????????????basicProperties.CorrelationId = correlationId; ???????????????channel.BasicPublish(exchange, routingKey, basicProperties, body.SerializeUtf8()); ???????????????var sw = Stopwatch.StartNew(); ???????????????while (true) ???????????????{ ???????????????????var ea = consumer.Queue.Dequeue(); ???????????????????if (ea.BasicProperties.CorrelationId == correlationId) ???????????????????{ ???????????????????????return ea.Body.DeserializeUtf8(); ???????????????????} ???????????????????if (sw.ElapsedMilliseconds > 30000) ???????????????????????throw new Exception("等待响应超时"); ???????????????} ???????????} ???????????catch (Exception ex) ???????????{ ???????????????throw ex.GetInnestException(); ???????????} ???????} ???????????/// <summary> ???????/// RPC服务端 ???????/// </summary> ???????/// <typeparam name="T"></typeparam> ???????/// <param name="exchange"></param> ???????/// <param name="queue"></param> ???????/// <param name="isProperties"></param> ???????/// <param name="handler"></param> ???????/// <param name="isDeadLetter"></param> ???????public void RpcService<T>(string exchange, string queue, bool isProperties, Func<T, T> handler, bool isDeadLetter) ???????{ ???????????//队列声明 ???????????var channel = GetModel(queue, isProperties); ???????????var consumer = new EventingBasicConsumer(channel); ???????????consumer.Received += (model, ea) => ???????????{ ???????????????var body = ea.Body; ???????????????var msgStr = body.DeserializeUtf8(); ???????????????var msg = msgStr.FromJson<T>(); ???????????????var props = ea.BasicProperties; ???????????????var replyProps = channel.CreateBasicProperties(); ???????????????replyProps.CorrelationId = props.CorrelationId; ???????????????try ???????????????{ ???????????????????msg = handler(msg); ???????????????} ???????????????catch (Exception ex) ???????????????{ ???????????????????ex.GetInnestException().WriteToFile("队列接收消息", "RabbitMq"); ???????????????} ???????????????finally ???????????????{ ???????????????????channel.BasicPublish(exchange, props.ReplyTo, replyProps, msg.ToJson().SerializeUtf8()); ???????????????????channel.BasicAck(ea.DeliveryTag, false); ???????????????} ???????????}; ???????????channel.BasicConsume(queue, false, consumer); ???????}可以用，但不建议去用。可以考虑其他的RPC框架。grpc、thrift等。
结尾
本篇文章，没有过多的写RabbitMq的知识点，因为园子的学习笔记实在太多了。下面把我的代码奉上 https://github.com/SkyChenSky/RabbitMq 。如果有发现写得不对的地方麻烦在评论指出，我会及时修改以免误导别人。
如果本篇文章您有用，请点击一下推荐，谢谢大家阅读。
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原文地址：https://www.cnblogs.com/lonelyxmas/p/10309429.html