无法使用EMS.NET API从主题检索消息 [英] Not able to retrieve messages from topic using EMS.NET API

问题描述

我正在尝试编写一个简单的应用程序，以通过使用输入向主题发送消息并显示在该主题上发布的消息. 有两个命令行可执行文件-一个用于发布者，另一个用于订阅者. 当我发布有关某个主题的消息时，我可以看到这些消息已提交给该主题.

I am trying to write a simple application to send messages to a topic from use input and show messages published on topic. There are two command line executables - one for publisher and another for subscriber. When I publish messages on a topic, I can see the messages getting submitted to the topic.

以下命令显示有关该主题的消息(请参阅F1.gif):-

The following command shows that there are messages on the topic (see F1.gif):-

show stat EMS.Test.Topic

以下命令显示消息已被订阅者使用(请参阅F2.gif)

The following command shows that the messages are getting consumed by the subscribers (see F2.gif)

show stat consumers topic=EMS.Test.Topic

但是，我无法检索EMS .NET API的消息.它卡在Message msg = subscriber.Receive();上.我确保连接详细信息和身份验证详细信息正确无误，因为它们在发布消息时使用.

However, I am not able to retrieve messages the EMS .NET API. It gets stuck on Message msg = subscriber.Receive();. I made sure the connection details and authentication details are correct because they are used when publishing the messages.

public string ReceiveMessagesFromTopic(string topicName)
        {
            TopicConnection connection = null;
            string messageFromPublisher = string.Empty;
            try
            {
                var factory = new TIBCO.EMS.TopicConnectionFactory(serverUrl);
                connection = factory.CreateTopicConnection(userName, password);
                TopicSession session = connection.CreateTopicSession(false, Session.AUTO_ACKNOWLEDGE);
                Topic topic = session.CreateTopic(topicName);
                TopicSubscriber subscriber = session.CreateSubscriber(topic);
                connection.Start();
                while (true)
                {
                   Message msg = subscriber.Receive();
                    if (msg == null)
                    {
                        break;
                    }
                    if (msg is TextMessage)
                    {
                        TextMessage tm = (TextMessage) msg;
                        messageFromPublisher = tm.Text;
                    }

                }
                connection.Close();
            }
            catch (EMSException e)
            {
                if (connection!=null)
                {
                    connection.Close();
                }


                throw;
            }

            return messageFromPublisher;
        }

推荐答案

.NET代码中存在一个愚蠢的错误.接下来的while循环永不返回，因此没有返回.收到消息时，我需要中断while循环. h !!!!

There was a silly mistake in my .NET code. the following while loop never returns so there is no return. I need to break the while loop when I get a message. Duh!!!!

 while (true)
 {
         Message msg = subscriber.Receive();

         if (msg == null)
         {
             break;
         }
         if (msg is TextMessage)
         {
             TextMessage tm = (TextMessage) msg;
             messageFromPublisher = tm.Text;
             break;
         }

 }

这篇关于无法使用EMS.NET API从主题检索消息的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！