原文:
Producer：消息的生产者，也就是创建消息的对象
Exchange：消息的接受者，也就是用来接收消息的对象，Exchange接收到消息后将消息按照规则发送到与他绑定的Queue中。下面我们来定义一个Producer与Exchange。
1.新建.netcore console项目，并引入RabbitMQ.Client的Nuget包
2.创建Exchange
using RabbitMQ.Client;namespace RabbitMQConsole{ class Program { static void Main(string[] args) { ConnectionFactory factory = new ConnectionFactory(); factory.HostName = "39.**.**.**"; factory.Port = 5672; factory.VirtualHost = "/"; factory.UserName = "root"; factory.Password = "root"; var exchange = "change2"; var route = "route2"; var queue = "queue2"; using (var connection = factory.CreateConnection()) { using (var channel = connection.CreateModel()) { channel.ExchangeDeclare(exchange, type:"direct", durable: true, autoDelete: false); //创建Exchange } } } }} 可以看到Echange的参数有：
type：可选项为，fanout，direct，topic，headers。区别如下：
fanout：发送到所有与当前Exchange绑定的Queue中
direct：发送到与消息的routeKey相同的Rueue中
topic：fanout的模糊版本
headers：发送到与消息的header属性相同的Queue中
durable：持久化
autoDelete：当最后一个绑定（队列或者exchange）被unbind之后，该exchange自动被删除。
运行程序，可以在可视化界面看到change2
接下来我们可以创建与change2绑定的queue
3.创建Queue
using (var channel = connection.CreateModel()) { channel.ExchangeDeclare(exchange, type: "direct", durable: true, autoDelete: false); channel.QueueDeclare(queue, durable: true, exclusive: false, autoDelete: false); #创建queue2 channel.QueueBind(queue, exchange, route); #将queue2绑定到exchange2 } 可以看到Echange的参数有：
durable：持久化
exclusive：如果为true，则queue只在channel存在时存在，channel关闭则queue消失
autoDelete：当最后一个绑定（队列或者exchange）被unbind之后，该exchange自动被删除。
去可视化界面看Queue
4.发送消息
using (var channel = connection.CreateModel()) { channel.ExchangeDeclare(exchange, type: "direct", durable: true, autoDelete: false); channel.QueueDeclare(queue, durable: true, exclusive: false, autoDelete: false); channel.QueueBind(queue, exchange, route); var props = channel.CreateBasicProperties(); props.Persistent = true; #持久化 channel.BasicPublish(exchange, route, true, props, Encoding.UTF8.GetBytes("hello rabbit")); } 
5.消费消息
using RabbitMQ.Client;using System;using System.Text;namespace RabbitMQClient{ class Program { private static readonly ConnectionFactory rabbitMqFactory = new ConnectionFactory() { HostName = "39.**.**.**", Port = 5672, UserName = "root", Password = "root", VirtualHost = "/" }; static void Main(string[] args) { var exchange = "change2"; var route = "route2"; var queue = "queue2"; using (IConnection conn = rabbitMqFactory.CreateConnection()) using (IModel channel = conn.CreateModel()) { channel.ExchangeDeclare(exchange, "direct", durable: true, autoDelete: false); channel.QueueDeclare(queue, durable: true, exclusive: false, autoDelete: false); channel.QueueBind(queue, exchange, route); while (true) { var message = channel.BasicGet(queue, true); #第二个参数说明自动释放消息，如为false需手动释放消息 if(message!=null) { var msgBody = Encoding.UTF8.GetString(message.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)); } System.Threading.Thread.Sleep(TimeSpan.FromSeconds(1)); } } } }} 运行查看结果
查看可视化界面
6.手动释放消息
while (true) { var message = channel.BasicGet(queue, false);#设置为手动释放 if(message!=null) { var msgBody = Encoding.UTF8.GetString(message.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.BasicAck(message.DeliveryTag, false); #手动释放 System.Threading.Thread.Sleep(TimeSpan.FromSeconds(1)); } 我们再发一条消息，然后开始消费，加个断点调试一下
查看一下Queue中消息状态
然后直接取消调试，不让程序走到释放的那一步，再查看一下消息状态
这么说来只要不走到 channel.BasicAck(message.DeliveryTag, false);这一行，消息就不会被释放掉，我们让程序直接走到这一行代码，查看一下消息的状态
如图已经被释放了
7.让失败的消息回到队列中
while (true) { var message = channel.BasicGet(queue, false); if(message!=null) { var msgBody = Encoding.UTF8.GetString(message.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)); Console.WriteLine(message.DeliveryTag); #当前消息被处理的次序数 if (1==1) channel.BasicReject(message.DeliveryTag, true); } System.Threading.Thread.Sleep(TimeSpan.FromSeconds(1)); } 重新发送4条消息
开始消费
我们可以看到消息一直没有没消费，因为消息被处理之后又放到了队尾
8.监听消息
using (IConnection conn = rabbitMqFactory.CreateConnection()) using (IModel channel = conn.CreateModel()) { channel.ExchangeDeclare(exchange, "direct", durable: true, autoDelete: false); channel.QueueDeclare(queue, durable: true, exclusive: false, autoDelete: false); channel.QueueBind(queue, exchange, route); channel.BasicQos(prefetchSize: 0, prefetchCount: 10, global: false); #一次接受10条消息，否则rabbit会把所有的消息一次性推到client，会增大client的负荷 EventingBasicConsumer consumer = new EventingBasicConsumer(channel); consumer.Received += (model, ea) => { Byte[] body = ea.Body; String message = Encoding.UTF8.GetString(body); Console.WriteLine( message+Thread.CurrentThread.ManagedThreadId); channel.BasicAck(deliveryTag: ea.DeliveryTag, multiple: false); }; channel.BasicConsume(queue: queue, autoAck: false, consumer: consumer); Console.ReadLine(); }