JMS MessageConsumer的messageListener是推还是拉? [英] JMS MessageConsumer's messageListener makes push or pull?

问题描述

当我在队列MessageConsumer对象上设置messageListener时，实际上发生了什么. MessageConsumer对象是否在场景中进行某种轮询，或者这是JMS服务器真正进行的推送?

What really happens under the hood when i set a messageListener on my queue MessageConsumer object. Does the MessageConsumer object make some sort of polling ehind the scene or this is a real push made by the JMS server?

David A. Chappell，Richard Monson-Haefel和Mark Richards撰写的Java消息服务(O'Reilly Java系列)，第10章第1章:点对点

Java Message Service (O'Reilly Java Series) by David A. Chappell, Richard Monson-Haefel and Mark Richards, p10 CHAPTER1: Point-to-point

点对点消息传递模型传统上是基于拉式或基于轮询的模型，在这种模型中，消息是从队列中请求的，而不是自动发送到客户端的

http://docs.oracle.com/javaee/1.4/tutorial/doc/JMS4.html#wp79175

开始传递消息时，只要传递消息，JMS提供程序就会自动调用消息侦听器的onMessage方法.

谢谢， 柯德

推荐答案

这两个并不矛盾. P2P本质上是基于拉的，因为一旦生产者发送了消息，接收者有责任读取消息.您在第二个引号中提到的onMessage()方法是用于启动请求的 notification 机制.这些变体也称为接收JMS消息的同步与异步模式，例如在

These two do not contradict each other. P2P is essentially pull-based, in that it is receiver's responsibility to read a message once it is sent by a producer. onMessage() method that you mentioned in your 2nd quote is a notification mechanism used to initiate the pull. These variations also referred to as sync vs async modes of receiving JMS messages, as for example in this chapter in Java Tutorial.

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