上次我们介绍了在单机、集群下高并发场景可以选择的一些方案，
但是也发现了一些问题，比如集群下使用ConcurrentQueue或加锁都不能解决问题，后来采用Redis队列也不能完全解决问题，
因为使用Redis要自己实现分布式锁
这次我们来了解一下一个专门处理队列的组件：RabbitMQ，这个东西天生支持分布式队列。
下面我们来用RabbitMQ来实现上一篇的场景
一、新建RabbitMQ.Receive
private static ConnectionFactory factory = new ConnectionFactory
{ HostName = "192.168.1.109", UserName = "ljr", Password = "root", VirtualHost = "/" };
1 static void Main(string[] args)
2 {
3 using (var connection = factory.CreateConnection())
4 {
5 using (var channel = connection.CreateModel())
6 {
7 var consumer = new EventingBasicConsumer();
8 consumer.Received += (model, ea) =>
9 {
10 var body = ea.Body;
11 var message = Encoding.UTF8.GetString(body);
12 Console.WriteLine(" [x] Received {0}", message);
13
14 var total = DbHelper.ExecuteScalar("Select Total from ConCurrency where Id = 1", null).ToString();
15 var value = int.Parse(total) + 1;
16
17 DbHelper.ExecuteNonQuery(string.Format("Update ConCurrency Set Total = {0} where Id = 1", value.ToString()), null);
18 };
19
20 channel.QueueDeclare(queue: "queueName", durable: false, exclusive: false, autoDelete: false, arguments: null);
21 channel.BasicConsume(queue: "queueName", noAck: true, consumer: consumer);
22
23 Console.WriteLine(" Press [enter] to exit.");
24 Console.ReadLine();
25 }
26 }
27 }
二、新建RabbitMQ.Send
1 static void Main(string[] args)
2 {
3 for (int i = 1; i <= 500; i++)
4 {
5 Task.Run(async () =>
6 {
7 await Produce();
8 });
9
10 Console.WriteLine(i);
11 }
12
13 Console.ReadKey();
14 }
15
16 public static Task Produce()
17 {
18 return Task.Factory.StartNew(() =>
19 {
20 using (var connection = factory.CreateConnection())
21 {
22 using (var channel = connection.CreateModel())
23 {
24 var body = Encoding.UTF8.GetBytes(Guid.NewGuid().ToString());
25 channel.QueueDeclare(queue: "queueName", durable: false, exclusive: false, autoDelete: false, arguments: null);
26 channel.BasicPublish(exchange: "", routingKey: "queueName", basicProperties: null, body: body);
27 }
28 }
29 });
30 }
这里是模拟500个用户请求，正常的话最后Total就等于500
我们来说试试看，运行程序
2.1、打开接收端
2.2 运行客户端
2.3、可以看到2边几乎是实时的，再去看看数据库
三、我们在集群里执行
最后数据是1000
完全没有冲突，好了，就是这样 、。
