"Activemq-5" activemq Comparison of learning-queue and topic

A comparison between Queue and Topic

1 ,JMS Queue Execute Load balancer semantics:

A message can only be received by one consumer .

If there is no consumeravailable when the message is sent, it will be saved until the consumer that can handle the message is available.

If a consumer receives a message and does not respond to it, then the message will be transferred to another consumer .

A Queue can have a lot of consumerand load balance in multiple available consumer .

How to understand: if a consumer receives a message and does not respond to it, then the message will be transferred to another consumer .

See the procedure in the annex:

in the Receiver.java, Create a consumer and achieve a synchronous receive:

  
 

   
  

  
while (true) {
   
  

  
// 设置接收者接收消息的时间，为了便于测试，这里谁定为100s
   
  

  
TextMessage message = (TextMessage) consumer.receive(18000);
   
  

  
// Object message = (Object) consumer.receive(28000);
   
  

  
if (null != message) {
   
  

  
System.out.println("订阅者1：收到消息-->" + message.getText());
   
  

  
} else {
   
  

  
System.out.println("订阅者1：运行结束...\n");
   
  

  
break;
   
  

  
}
   
  

  
}
  
 

in the Receiver2.java, the program that created the consumer but commented out the receiving part:

  
 

   
  

  
//while (true) {
   
  

  
//// 设置接收者接收消息的时间，为了便于测试，这里谁定为100s
   
  

  
//TextMessage message = (TextMessage) consumer.receive(18000);
   
  

  
//if (null != message) {
   
  

  
//System.out.println("订阅者2：收到消息-->" + message.getText());
   
  

  
//} else {
   
  

  
//System.out.println("订阅者2：消费者运行结束...\n");
   
  

  
//break;
   
  

  
//}
   
  

  
//}
  
 

First, separate thereceiver andReceiver2 Run and then run sender, you will get the following results:

Special Note: Subscriber 2 stops after subscriber 1, how to stop before Subscribers 1, the result is not the same.
When you turn on receive1 again, you will see:

if Subscriber 2 stops before Subscriber 1, and the following results will appear:

2 ,Topic implement Publish and Subscribe semantics:

When a message is publish , it will be sent to all interested subscribers, so 0 to multiple Subscriber will receive a copy of the message. However, when the message agent receives a message, only the subscriber that activates the subscription can get a copy of the message.

3 , respectively, corresponding to two message modes:

Point-to-Point ( Point-to-point ), Publisher/subscriber Model ( publisher / subscriber )

Where in publicher/subscriber mode There are nondurable subscription(non-persistent subscriptions) and Durable subscription ( persistent subscription ) 2 kinds of message processing methods.

 




From for notes (Wiz)

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"Activemq-5" activemq Comparison of learning-queue and topic