如何使用JMS基于Activemq消息调用externalApplication [英] How can I call externalApplication based on Activemq message using JMS

问题描述

我构建3个应用程序，每个应用程序需要20多分钟进行评估。我在以下目录中放置了3个文件

I build 3 Applications,each Application takes more than 20 min for evaluation.I placed 3 files in the following directories

 ProjectcContextPath/WEB-INF/classes/PackageName/ExternalFileProcess.class

 ProjectcContextPath/JSPFiles/index.jsp

ProjectcContextPath/WEB-INF/classes/AnotherFile.class

我想从另一个 Java 文件中调用这3个应用程序名称为 MessageConsumer.java ，基于message-head。这些消息来自 Activemq 。

I want to call these 3 Applications from another Java file name as MessageConsumer.java,based on message-head.These messages are fetching from Activemq.

我不想一次获取所有消息。一旦之前完成，那么只有 MessageConsumer.java 从 Activemq 获取另一条消息。

I don't want to fetch all the messages at a time. once previous is completed then only it MessageConsumer.java fetch another message from Activemq.

为了更好地理解我做了一些模拟。检查它们。检查后你们会明白的。

For your better understanding I made some mock-ups.check them.After check that you guys will understand clearly.

工作流程：

Xml数据结构。

我做了什么：

1. 我构建了最终的3个应用程序，它们工作正常。

1. I build final 3 Applications,they are working fine.

我写了一个函数，如果你传递xmlfilepath和Message-head值作为参数，那么它返回对应的 ApplicationRealPath 标签值。

I wrote a function,If you pass xmlfilepath and Message-head values as a parameters,then it returns corresponding ApplicationRealPath tag value.

我想做什么：

1. 我想从 Activemq

从混乱中找到消息头age

Find message-head from message

将message-head和xml文件路径传递给另一个函数。获取相应的 ApplicationRealPath 值。

pass message-head and xml file path to another function.Getting corresponding ApplicationRealPath value .

并触发该应用程序。

从 Activemq ，一旦上一次触发申请流程完成

fetch one more message from Activemq,once previous triggered Application process is done

我真的想从3天，我仍然没弄清楚。我尝试了以下代码。它无法正常工作

Really I am trying this from 3 days, still I didn't figure it out.I tried the following code.it's not working

   package PackageName;
   import java.io.IOException;
   import javax.servlet.RequestDispatcher;
   import javax.servlet.ServletException;
   import javax.servlet.http.HttpServlet;
   import javax.servlet.http.HttpServletRequest;
  import javax.servlet.http.HttpServletResponse;
  import javax.jms.*;
  import org.apache.activemq.ActiveMQConnectionFactory;
  public class MessageConsumer extends HttpServlet {
 @Override
  protected void service(HttpServletRequest request, HttpServletResponse response)
     throws ServletException, IOException {
try {
//creating connectionfactory object for way
ConnectionFactory connectionFactory=new     
 ActiveMQConnectionFactory("admin","admin","tcp://localhost:61617");
 //establishing the connection b/w this Application and Activemq
Connection connection=connectionFactory.createConnection();
QueueSession session=(QueueSession) connection.createSession(false, Session.CLIENT_ACKNOWLEDGE);
Queue queue=session.createQueue("MessageTesing");
final QueueReceiver queueReceiver =session.createReceiver(queue);
connection.start();
while (true) {
  Message message = queueReceiver.receive();
  message.acknowledge();
  TextMessage textmsg=(TextMessage) message;
  if (textmsg.getText()=="TestMessage35") {
      RequestDispatcher rd=request.getRequestDispatcher("servletName");
      rd.forward(request, response ) ;
      System.out.println(textmsg.getJMSDestination());
 }
  }
 }
  catch (Exception e) {
  // TODO: handle exception
}
 }
 }

我是java的新手，能用代码清楚解释。

I am new to java, can you explain clearly with code.

谢谢。

推荐答案

根据这些要求

• 当数据库中的数据发生变化时，会在队列中发布消息。


• 根据消息内容动态调用其他服务。


• 该服务进行一些计算，但其结果不适用于最终用户。需要20分钟。

你可以实现一个独立的应用程序，它可以像这样同步接收消息（伪代码）：

you could implement a stand-alone application which receives messages synchronously like this (pseudo code):

while (true) {
  Message message = queueReceiver.receive();
  TextMessage textmsg = (TextMessage) message;

  if (textmsg.getText().equals("service1")) {
    new Service1().execute();
  } else if (textmsg.getText().equals("service2")) {
    new Service2().execute();
  } else {
    // Show error
  }
  message.acknowledge();
}

此作业持续运行。

与提案的差异

• 使用独立程序（带有一个 main 方法）而不是servlet。 servlet不适合（因为它不能连续运行）。


• 将服务实现为普通的Java类;调用JSP或servlet进行处理是没用的。它们旨在实现表示层

• Using a stand-alone program (with a main method) instead of a servlet. A servlet is not suitable (because it does not run continuously)
• Implement your services as normal Java classes; calling JSPs or servlets for processing is not useful. They are intended to implement the presentation layer

更新

如果您的服务只能通过HTTP访问（这是servlets / JSP的情况），那么您可以将它们实现为 Web服务。

If your services are only reachable over HTTP (this is the case with servlets/JSP), then you could implement these as a web service.

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