RabbitMQ AMQP Java客户端关闭处理程序的用途是什么？

Question

The RabbitMQ documentation presents how to add a shutdown listener and when the listener is called but I fail to see on what purpose the handler is for. Seems that all the Java examples (including https://github.com/rabbitmq/rabbitmq-tutorials ) out there ignore shutdown handlers. In which cases should I prefer shutdown listener over simply catching ShutdownSignalException (and IOException ) exception ?

Another puzzling issue is that where the control flow goes when the handler has finished.

Potentially relevant related SO questions:

• What is the best way to safely end a java application with running RabbitMQ consumers
• Using RabbitMQ (Java client), is there a way to determine if network connection is closed during consume?

Answer 1

Catching IOException can tell you if a connection/channel shutdown occurred as the result of a method invocation, but connections/channels can also be shutdown involuntarily such as if the connection to the server is lost. In this case a ShutdownListener is the only way to learn of the connection/channel closure.

Shutdown listeners are often used to provide connection/channel recovery, though recovering reliably is a challenge of its own. For this, check out Lyra .

Answer 2

The main use of a ShutdownListener i've seen is to do automatic reconnection. You listen for a shutdown, and when it happens, try to reconnect.

For example, this is the basis of rabbitmq-ha-client , where it is done in HaConnectionFactory.HaShutdownListener .