Axon message receive but event handler not call

问题

Axon message receives but event handler not call.

I am trying to implement the event sourcing in both the side with tow different queue. My First Queue is test and the Second one is testdemo

I have two separate application running on the same server.

1. User Management
2. Wallet Management

I have implemented the event sourcing from User Management to wallet management. and it is working fine.

Now I am trying to implement the wallet management to UserManagement, Means that When I will publish the event from the wallet management ( Producer ) and ( Consume ) the user management application. So the event is received but event handler is not called.

Following is my application code. Please help me to figure out what I will be missing.

My Axon Configuration Class

package com.peaas.ngapblueprintdemo.config;

import org.axonframework.amqp.eventhandling.DefaultAMQPMessageConverter;
import org.axonframework.amqp.eventhandling.spring.SpringAMQPMessageSource;
import org.axonframework.serialization.Serializer;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.amqp.core.AmqpAdmin;
import org.springframework.amqp.core.Binding;
import org.springframework.amqp.core.BindingBuilder;
import org.springframework.amqp.core.Exchange;
import org.springframework.amqp.core.ExchangeBuilder;
import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.Queue;
import org.springframework.amqp.core.QueueBuilder;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import com.rabbitmq.client.Channel;

@Configuration
public class AxonConfiguration {

    private final static Logger logger = LoggerFactory.getLogger(AxonConfiguration.class);

    @Value("${axon.amqp.exchange}")
    private String exchange;

    @Bean
    public Exchange exchange() {
        logger.info(exchange + " AMQP Exchange Registering ");
        return ExchangeBuilder.fanoutExchange(exchange).build();
    }

    @Bean
    public Queue queue() {
        return QueueBuilder.durable(exchange).build();
    }

    @Bean
    public Binding binding() {
        return BindingBuilder.bind(queue()).to(exchange()).with("*").noargs();
    }

    @Autowired
    public void configure(AmqpAdmin amqpAdmin) {
        amqpAdmin.declareExchange(exchange());
        amqpAdmin.declareQueue(queue());
        amqpAdmin.declareBinding(binding());
    }   

    @Bean
    public SpringAMQPMessageSource testdemo(Serializer serializer) {
        System.out.println("--- On Message Call ---");
        return new SpringAMQPMessageSource(new DefaultAMQPMessageConverter(serializer)) {

            @RabbitListener(queues = "testdemo")

            @Override
            public void onMessage(Message message, Channel channel) throws Exception {
                System.out.println(message.getMessageProperties());
                System.out.println("channel == "+channel);
                super.onMessage(message, channel);
            }
        };
    }
}

WalletCreatedEvent Class

package com.peaas.ngapblueprintdemo.events;

public class WalletCreatedEvent {
    private Long id;
    private String walletId;
    private Double amount;
    private Long userId;

    public WalletCreatedEvent(Long id, String walletId, Double amount, Long userId) {       
        super();
        System.out.println("--- call ---");
        this.id = id;
        this.walletId = walletId;
        this.amount = amount;
        this.userId = userId;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Double getAmount() {
        return amount;
    }

    public void setAmount(Double amount) {
        this.amount = amount;
    }

    public Long getUserId() {
        return userId;
    }

    public void setUserId(Long userId) {
        this.userId = userId;
    }

    public String getWalletId() {
        return walletId;
    }

    public void setWalletId(String walletId) {
        this.walletId = walletId;
    }

    @Override
    public String toString() {
        return "WalletCreatedEvent [id=" + id + ", walletId=" + walletId + ", amount=" + amount + ", userId=" + userId
                + "]";
    }

}

EventHandler Class

package com.peaas.ngapblueprintdemo.eventHandlers;

import org.axonframework.eventhandling.EventHandler;
import org.springframework.stereotype.Component;

import com.peaas.ngapblueprintdemo.events.WalletCreatedEvent;

@Component
public class UserEventHandler {

    @EventHandler
    public void onCreateWalletEvent(WalletCreatedEvent event) {
        System.out.println("--- Wallet Created Successfully ---");
        System.out.println(event);
    }   
}

Following is my application.yml file properties

axon:
    amqp:
        exchange: test
    eventhandling:
        processors:
            amqpEvents:
                source: testdemo

Following is my log data that showing event is received.

MessageProperties [headers={axon-message-id=fa60968c-6905-46b5-8afe-6da853a4c51a, axon-message-aggregate-seq=0, axon-metadata-correlationId=589ef284-176f-49b8-aae0-0ad1588fa735, axon-message-aggregate-type=WalletAggregate, axon-message-revision=null, axon-message-timestamp=2018-08-06T11:09:26.345Z, axon-message-type=com.peaas.ngapblueprintdemo.events.WalletCreatedEvent, axon-metadata-traceId=589ef284-176f-49b8-aae0-0ad1588fa735, axon-message-aggregate-id=9524f7df-44fb-477f-83b8-d176583a126e}, contentLength=0, receivedDeliveryMode=PERSISTENT, redelivered=false, receivedExchange=testdemo, receivedRoutingKey=com.peaas.ngapblueprintdemo.events, deliveryTag=1, consumerTag=amq.ctag-fGm3jQcP_JIoTGf4ZMhAIg, consumerQueue=testdemo]
channel == Cached Rabbit Channel: AMQChannel(amqp://guest@127.0.0.1:5672/,1), conn: Proxy@3dcd657d Shared Rabbit Connection: SimpleConnection@19b12fd2 [delegate=amqp://guest@127.0.0.1:5672/, localPort= 52963]

回答1:

You have most of the right configuration in place, but you are forgetting to tie your SpringAMQPMessageSource to an Event Processor under which your event handling component is placed.

See the reference guide for a correct example on how to reach this.

Here is a direct snippet from that reference guide to configure the message source to an event processor:

@Autowired
public void configure(EventHandlingConfiguration ehConfig, SpringAmqpMessageSource myMessageSource) {
ehConfig.registerSubscribingEventProcessor("myProcessor", c -> myMessageSource);
}

Edit

I think I see which part you where missing. You did correctly wire the queue as a subscribable message source to an Event Processor. This follows from you application.yml, which ties the testdemo message source to the amqpEvents Event Processor. Thus sorry for my earlier assumption on that part.

The reasoning why you don't receive your events in the UserEventHandler, is because that event handler isn't tied to the amqpEvents Event Processor. To solve that you should add the @ProcessingGroup("amqpEvents") annotation to the UserEventHandler component.

来源：https://stackoverflow.com/questions/51706295/axon-message-receive-but-event-handler-not-call