rabbitmq(5)rpc模式

rpc采用确认模式，client发送消息至server并等待消息回传，server接到消息并处理后回传给client,中间通过Correlation Id来确认消息，amqp协议下，代码如下
Tut6Config.java

@Profile({"tut6","rpc"})
@Configuration
public class Tut6Config {
    @Profile("client")
    private static class ClientConfig {

        @Bean
        public DirectExchange exchange() {
            return new DirectExchange("tut.rpc");
        }

        @Bean
        public Tut6Client client() {
            return new Tut6Client();
        }

    }

    @Profile("server")
    private static class ServerConfig {

        @Bean
        public Queue queue() {
            return new Queue("tut.rpc.requests");
        }

        @Bean
        public DirectExchange exchange() {
            return new DirectExchange("tut.rpc");
        }

        @Bean
        public Binding binding(DirectExchange exchange,
                               Queue queue) {
            return BindingBuilder.bind(queue)
                    .to(exchange)
                    .with("rpc");
        }

        @Bean
        public Tut6Server server() {
            return new Tut6Server();
        }

    }
}

Tut6Client.java
需要注意的是，client等待消息接收，若发送消息未接到返回则报异常，可用try-catch接收

public class Tut6Client {
    @Autowired
    private RabbitTemplate template;

    @Autowired
    private DirectExchange exchange;

    int start = 0;

    @Scheduled(fixedDelay = 1000, initialDelay = 500)
    public void send() {
        System.out.println(" [x] Requesting fib(" + start + ")");
        Integer response = 0;
        try{
            response = (Integer) template.convertSendAndReceive
                    (exchange.getName(), "rpc", start++);
        }catch (Exception e){
            System.out.println("服务端未直接终端了");
            e.printStackTrace();
        }

        System.out.println(" [.] Got '" + response + "'");
    }
}

Tut6Server.java

public class Tut6Server {
    @RabbitListener(queues = "tut.rpc.requests")
    // @SendTo("tut.rpc.replies") used when the
    // client doesn't set replyTo.
    public int fibonacci(int n) {
        System.out.println(" [x] Received request for " + n);
        int result = fib(n);
        System.out.println(" [.] Returned " + result);
        return result;
    }

    public int fib(int n) {
        return n == 0 ? 0 : n == 1 ? 1 : (fib(n - 1) + fib(n - 2));
    }
}