《《rabbitmq Java入门教程》.pdf

Introduction RabbitMQ is a message broker. In essence, it accepts messages from producers, and delivers them to consumers. In-between, it can route, buffer, and persist the messages according to rules you give it. RabbitMQ, and messaging in general, uses some jargon. • Producing means nothing more than sending. A program that sends messages is a producer . Well draw it like that, with P: • A queue is the name for a mailbox. It lives inside RabbitMQ. Although messages flow through RabbitMQ and your applications, they can be stored only inside a queue. A queue is not bound by any limits, it can store as many messages as you like - its essentially an infinite buffer. Many producers can send messages that go to one queue - many consumers can try to receive data from one queue. A queue will be drawn like this, with its name above it: • Consuming has a similar meaning to receiving. A consumer is a program that mostly waits to receive messages. On our drawings its shown with C: Note that the producer, consumer, and broker do not have to reside on the same machine; indeed in most applications they dont. Hello World (using the Java Client) In this part of the tutorial well write two programs in Java; a producer that sends a single message, and a consumer that receives messages and prints them out. Well gloss over some of the detail in the Java API, concentrating on this very simple thing just to get started. Its a Hello World of messaging. In the diagram below, P is our producer and C is our consumer. The box in the middle is a queue - a message buffer that RabbitMQ keeps on behalf of the consumer. The Java client library RabbitMQ speaks AMQP, which is