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spring-bootrabbitmqspring-integrationmessagingspring-amqp

Spring Boot + Spring Integration (AMQP)

I have been reading through the documentation for Spring Integration, but I still can't figure out how to model the following integration:

+----------+  --- (request) --> +----------+ --- (request) --> +----------+
| Service1 |                    | RabbitMQ |                   | Service2 |
+----------+  <--- (reply) ---- +----------+ <--- (reply) ---- +----------+

Basically what I would like to be able to do is to share an interface between Service 1 and Service 2, say

public interface Service2 {
    int sum(int a, int b);

    int subtract(int a, int b);
}

and be able to call

service2proxyInstance.sum(1, 2)

on some kind auto-generated proxy class inside Service1.

From what I read I think I must use an OutboundGateway in Service1 and an InboundGateway in Service2, but I can't seem to put them together. Could anyone please shed some light and maybe provide a very simple example? All the examples in Spring Integration seem to use XML configuration, but as I am pretty new to Spring and used to annotation-based config I can't read them adequately.

Solution

  • Not sure how to help you since you have already said everything correctly.

    Your service one should be as a @MessagingGateway or call such one. That should send a message to a channel for the AmqpOutboundEndpoint and wait for reply from there. That is really done automatically by @MessagingGateway.

    You payload will be serialized if it is POJO not String or something for JSON-marshalling.

    Another application should start from the AmqpInboundGateway, send a request to the Service2 for the deserialized payload and wait for the reply from there to send back to your Service1 in the end.

    Take a look into Spring Integration Java DSL and AMQP tests there.

    And share you PoC and your concerns therefor better understanding what's going on.