Only a topic couples the publisher and subscriber; publishers publish to a topic and subscribers subscribe to a topic.
只有主题将发布者和订阅者联系起来；发布者发布某个主题，而订阅者则订阅该主题。
2
The match may be exact if the publisher and subscriber specify exactly the same topic name, or the subscriber may specify a wildcard to match many different published topics.
The PubSubRealTime application creates a JMS publisher and subscriber — the publisher sends a set number of messages that are then received by the subscriber.