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ActiveMQ在C#中的应用示例分析

本文实例讲述了ActiveMQ在C#中的应用。分享给大家供大家参考,具体如下:

ActiveMQ是个好东东,不必多说。ActiveMQ提供多种语言支持,如Java, C, C++, C#, Ruby, Perl, Python, PHP等。由于我在windows下开发GUI,比较关心C++和C#,其中C#的ActiveMQ很简单,Apache提供NMS(.Net Messaging Service)支持.Net开发,只需如下几个步骤即能建立简单的实现。C++的应用相对麻烦些,后面会有文章介绍。

1、去ActiveMQ官方网站下载最新版的ActiveMQ,网址:http://activemq.apache.org/download.html。我之前下的是5.3.1,5.3.2现在也已经出来了。

2、去ActiveMQ官方网站下载最新版的Apache.NMS,网址:http://activemq.apache.org/nms/download.html,需要下载Apache.NMS和Apache.NMS.ActiveMQ两个bin包,如果对源码感兴趣,也可下载src包。这里要提醒一下,如果下载1.2.0版本的NMS.ActiveMQ,Apache.NMS.ActiveMQ.dll在实际使用中有个bug,即停止ActiveMQ应用时会抛WaitOne函数异常,查看src包中的源码发现是由于Apache.NMS.ActiveMQ-1.2.0-src\src\main\csharp\Transport\InactivityMonitor.cs中的如下代码造成的,修改一下源码重新编译即可。看了一下最新版1.3.0已经修复了这个bug,因此下载最新版即可。

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private void StopMonitorThreads()

{

   lock (monitor)

   {

     if (monitorStarted.CompareAndSet( true , false ))

     {

       AutoResetEvent shutdownEvent = new AutoResetEvent( false );

       // Attempt to wait for the Timers to shutdown, but don't wait

       // forever, if they don't shutdown after two seconds, just quit.

       this .readCheckTimer.Dispose(shutdownEvent);

       shutdownEvent.WaitOne(TimeSpan.FromMilliseconds(2000));

       this .writeCheckTimer.Dispose(shutdownEvent);

       shutdownEvent.WaitOne(TimeSpan.FromMilliseconds(2000));

       //WaitOne的定义:public virtual bool WaitOne(TimeSpan timeout,bool exitContext)

       this .asyncTasks.Shutdown();

       this .asyncTasks = null ;

       this .asyncWriteTask = null ;

       this .asyncErrorTask = null ;

     }

   }

}

3、运行ActiveMQ,找到ActiveMQ解压后的bin文件夹:...\apache-activemq-5.3.1\bin,执行activemq.bat批处理文件即可启动ActiveMQ服务器,默认端口为61616,这可在配置文件中修改。

4、写C#程序实现ActiveMQ的简单应用。新建C#工程(一个Producter项目和一个Consumer项目),WinForm或Console程序均可,这里建的是Console工程,添加对Apache.NMS.dll和Apache.NMS.ActiveMQ.dll的引用,然后即可编写实现代码了,简单的Producer和Consumer实现代码如下:

producer:

?

using System;

using System.Collections.Generic;

using System.Text;

using Apache.NMS;

using Apache.NMS.ActiveMQ;

using System.IO;

using System.Xml.Serialization;

using System.Runtime.Serialization.Formatters.Binary;

namespace Publish

{

   class Program

   {

     static void Main( string [] args)

     {

       try

       {

         //Create the Connection Factory

         IConnectionFactory factory = new ConnectionFactory( "tcp://localhost:61616/" );

         using (IConnection connection = factory.CreateConnection())

         {

           //Create the Session

           using (ISession session = connection.CreateSession())

           {

             //Create the Producer for the topic/queue

             IMessageProducer prod = session.CreateProducer(

               new Apache.NMS.ActiveMQ.Commands.ActiveMQTopic( "testing" ));

             //Send Messages

             int i = 0;

             while (!Console.KeyAvailable)

             {

               ITextMessage msg = prod.CreateTextMessage();

               msg.Text = i.ToString();

               Console.WriteLine( "Sending: " + i.ToString());

               prod.Send(msg, Apache.NMS.MsgDeliveryMode.NonPersistent, Apache.NMS.MsgPriority.Normal, TimeSpan.MinValue);

               System.Threading.Thread.Sleep(5000);

               i++;

             }

           }

         }

         Console.ReadLine();

       }

       catch (System.Exception e)

       {

         Console.WriteLine( "{0}" ,e.Message);

         Console.ReadLine();

       }

     }

   }

}

consumer:

?

using System;

using System.Collections.Generic;

using System.Text;

using Apache.NMS;

using Apache.NMS.ActiveMQ;

using System.IO;

using System.Xml.Serialization;

using System.Runtime.Serialization.Formatters.Binary;

namespace Subscribe

{

   class Program

   {

     static void Main( string [] args)

     {

       try

       {

         //Create the Connection factory

         IConnectionFactory factory = new ConnectionFactory( "tcp://localhost:61616/" );

         //Create the connection

         using (IConnection connection = factory.CreateConnection())

         {

           connection.ClientId = "testing listener" ;

           connection.Start();

           //Create the Session

           using (ISession session = connection.CreateSession())

           {

             //Create the Consumer

             IMessageConsumer consumer = session.CreateDurableConsumer( new Apache.NMS.ActiveMQ.Commands.ActiveMQTopic( "testing" ), "testing listener" , null , false );

             consumer.Listener += new MessageListener(consumer_Listener);

             Console.ReadLine();

           }

           connection.Stop();

           connection.Close();

         }

       }

       catch (System.Exception e)

       {

         Console.WriteLine(e.Message);

       }

     }

     static void consumer_Listener(IMessage message)

     {

       try

       {

         ITextMessage msg = (ITextMessage)message;

         Console.WriteLine( "Receive: " + msg.Text);

       }

       catch (System.Exception e)

       {

         Console.WriteLine(e.Message);

       }

     }

   }

}

程序实现的功能:生产者producer建立名为testing的主题,并每隔5秒向该主题发送消息,消费者consumer订阅了testing主题,因此只要生产者发送testing主题的消息到ActiveMQ服务器,服务器就将该消息发送给订阅了testing主题的消费者。

编译生成producer.exe和consumer.exe,并执行两个exe,即可看到消息的发送与接收了。

这个例子是建的主题(Topic),ActiveMQ还支持另一种方式:Queue,即P2P,两者有什么区别呢?区别在于,Topic是广播,即如果某个Topic被多个消费者订阅,那么只要有消息到达服务器,服务器就将该消息发给全部的消费者;而Queue是点到点,即一个消息只能发给一个消费者,如果某个Queue被多个消费者订阅,没有特殊情况的话消息会一个一个地轮流发给不同的消费者,比如:

msg1-->consumer A

msg2-->consumer B

msg3-->consumer C

msg4-->consumer A

msg5-->consumer B

msg6-->consumer C

特殊情况是指:ActiveMQ支持过滤机制,即生产者可以设置消息的属性(Properties),该属性与消费者端的Selector对应,只有消费者设置的selector与消息的Properties匹配,消息才会发给该消费者。Topic和Queue都支持Selector。

Properties和Selector该如何设置呢?请看如下代码:

producer:

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ITextMessage msg = prod.CreateTextMessage();

msg.Text = i.ToString();

msg.Properties.SetString( "myFilter" , "test1" );

Console.WriteLine( "Sending: " + i.ToString());

prod.Send(msg, Apache.NMS.MsgDeliveryMode.NonPersistent, Apache.NMS.MsgPriority.Normal, TimeSpan.MinValue);

consumer:

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//生成consumer时通过参数设置Selector

IMessageConsumer consumer = session.CreateConsumer( new Apache.NMS.ActiveMQ.Commands.ActiveMQQueue( "testing" ), "myFilter='test1'" );

希望本文所述对大家C#程序设计有所帮助。

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