java - 调度程序没有 channel “unknown.channel.name”的订阅者

Question

我正在尝试使用 spring 绑定(bind)来运行发布者和订阅者。

确保目的地(交换)是在rabbit-mq本地创建的。

发布者 (app.yml)

spring:
  cloud:
    stream:
      bindings:
        output:
          destination: HelloDestination
  rabbitmq:
    addresses: xxx.xxx.xx.xxx

订阅者(app.yml)

spring:
  cloud:
    stream:
      bindings:
        input:
          destination: HelloDestination
  rabbitmq:
    addresses: xxx.xxx.xx.xxx
server:
  port: 8081

发布者 (pom.yml)

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-stream-rabbit</artifactId>
            <version>2.1.1.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-integration</artifactId>
        </dependency>

订阅者 (pom.yml)

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-stream-rabbit</artifactId>
            <version>2.1.1.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-integration</artifactId>
        </dependency>

发布者(源java文件)

@SpringBootApplication
@EnableBinding(Source.class)
public class Demo1Application {

    //@Autowired
    //private static MessageChannel output;

    public static void main(String[] args) {
        SpringApplication.run(Demo1Application.class, args);

        String sampleMessage = "Hello";
        Message<String> message =
                MessageBuilder.withPayload("Hello World").build();

        MessageChannel output = new DirectChannel();

        output.send(message);   

    }

}

//消费者(源文件)

@SpringBootApplication
@EnableBinding(Sink.class)
public class Demo2Application {

    public static void main(String[] args) {
        SpringApplication.run(Demo2Application.class, args);
    }

    @StreamListener(Sink.INPUT)
    public void listenerMethod(Message<String> message)
    {
        System.out.println("The Message is :"+message);
    }
}

//----

完成所有操作后，我看到创建的交换以及交换上的消息。消费者启动得很好。但是生产者在尝试发送带有错误消息的消息时卡住了

Exception in thread "main" org.springframework.messaging.MessageDeliveryException: Dispatcher has no subscribers for channel 'unknown.channel.name'.; nested exception is org.springframework.integration.MessageDispatchingException: Dispatcher has no subscribers, failedMessage=GenericMessage [payload=Hello World, headers={id=ccf86001-5dba-6c64-bc76-e1f58782de42, timestamp=1558883876384}], failedMessage=GenericMessage [payload=Hello World, headers={id=ccf86001-5dba-6c64-bc76-e1f58782de42, timestamp=1558883876384}]
    at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscribableChannel.java:77)
    at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:461)
    at org.springframework.integration.channel.AbstractMessageChannel.send(AbstractMessageChannel.java:401)
    at com.example.demo.Demo1Application.main(Demo1Application.java:29)
Caused by: org.springframework.integration.MessageDispatchingException: Dispatcher has no subscribers, failedMessage=GenericMessage [payload=Hello World, headers={id=ccf86001-5dba-6c64-bc76-e1f58782de42, timestamp=1558883876384}]
    at org.springframework.integration.dispatcher.UnicastingDispatcher.doDispatch(UnicastingDispatcher.java:138)
    at org.springframework.integration.dispatcher.UnicastingDispatcher.dispatch(UnicastingDispatcher.java:105)
    at org.springframework.integration.channel.AbstractSubscribableChannel.doSend(AbstractSubscri

我预计该消息会被阅读。

Answer 1

您需要从 run() 方法返回的应用程序上下文中获取 channel “输出”，而不是创建自己的 DirectChannel。