Spring集成网关“Dispatcher没有订阅者" [英] Spring integration gateway "Dispatcher has no subscribers"

问题描述

我在 outboundChannel 上遇到异常 Dispatcher has nosubscribes 并且无法弄清楚原因.我确信它很简单，我已经将我的代码剥离到下面的一个非常简单的示例中:

I am getting an exception Dispatcher has no subscribers on the outboundChannel and can't figure out why. I am sure its something simple, I have stripped back my code to a very simple sample below:

我的背景是:

<bean id="requestService"
    class="com.sandpit.RequestService" />

<integration:channel id="inboundChannel" />

<integration:service-activator id="service"
    input-channel="inboundChannel"
    output-channel="outboundChannel"
    ref="requestService"
    method="handleRequest" />

<integration:channel id="outboundChannel" />

<integration:gateway id="gateway"
    service-interface="com.sandpit.Gateway"
    default-request-channel="inboundChannel"
    default-reply-channel="outboundChannel" />

<bean class="com.sandpit.GatewayTester">
    <property name="gateway"
        ref="gateway" />
</bean>

我的 Java 代码是:

My Java code is:

public interface Gateway {

    String receive();
    void send(String message);
}

public class RequestService {

    public String handleRequest(String request) {

        return "Request received: " + request;
    }
}

public class GatewayTester implements ApplicationListener<ContextRefreshedEvent> {

    private Gateway gateway;

    public void setGateway(Gateway gateway) {

        this.gateway = gateway;
    }

    @Override
    public void onApplicationEvent(ContextRefreshedEvent event) {

        gateway.send("Hello world!");
        System.out.println("FROM SERVICE: " + gateway.receive());
    }
}

注意:断点确实告诉我 RequestService 实际上正在处理请求.

Note: A breakpoint does tell me that the RequestService is actually handling the request.

推荐答案

receive() 没有 args 需要回复频道是一个 PollableChannel 见 文档.

receive() with no args needs the reply channel to be a PollableChannel See the documentation.

将 添加到 outboundChannel.

或者，您可以将网关方法更改为 String sendAndReceive(String in) 并且一切都将按预期工作(您甚至可以完全删除 outboundChannel).

Alternatively, You could change your gateway method to be String sendAndReceive(String in) and all will work as expected (and you can even remove the outboundChannel altogether).

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