spring boot rabbitmq MappingJackson2MessageConverter 自定义对象转换

2022-01-11 00:00:00 json rabbitmq java spring-boot spring-amqp

我正在尝试使用 spring boot 创建一个简单的 spring boot 应用程序，该应用程序向 rabbitmq 交换/队列生成"消息，以及另一个使用"这些消息的示例 spring boot 应用程序.所以我有两个应用程序(如果你愿意，也可以是微服务).1)生产者"微服务2)消费者"微服务

I'm trying to create a simple spring boot app with spring boot that "produce" messages to a rabbitmq exchange/queue and another sample spring boot app that "consume" these messages. So I have two apps (or microservices if you wish). 1) "producer" microservice 2) "consumer" microservice

生产者"有 2 个域对象.Foo 和 Bar 应该被转换为 json 并发送到 rabbitmq.消费者"应该接收 json 消息并将其分别转换为域 Foo 和 Bar.由于某种原因，我无法完成这个简单的任务.这方面的例子不多.对于消息转换器，我想使用 org.springframework.messaging.converter.MappingJackson2MessageConverter

The "producer" has 2 domain objects. Foo and Bar which should be converted to json and send to rabbitmq. The "consumer" should receive and convert the json message into a domain Foo and Bar respectively. For some reason I can not make this simple task. There are not much examples about this. For the message converter I want to use org.springframework.messaging.converter.MappingJackson2MessageConverter

这是我目前所拥有的:

生产者微服务

package demo.producer;

import org.springframework.amqp.core.Binding;
import org.springframework.amqp.core.BindingBuilder;
import org.springframework.amqp.core.Queue;
import org.springframework.amqp.core.TopicExchange;
import org.springframework.amqp.rabbit.core.RabbitMessagingTemplate;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.messaging.converter.MappingJackson2MessageConverter;
import org.springframework.stereotype.Service;

@SpringBootApplication
public class ProducerApplication implements CommandLineRunner {

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

    @Bean
    Queue queue() {
        return new Queue("queue", false);
    }

    @Bean
    TopicExchange exchange() {
        return new TopicExchange("exchange");
    }

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

    @Bean
    public MappingJackson2MessageConverter jackson2Converter() {
        MappingJackson2MessageConverter converter = new MappingJackson2MessageConverter();
        return converter;
    }

    @Autowired
    private Sender sender;

    @Override
    public void run(String... args) throws Exception {
        sender.sendToRabbitmq(new Foo(), new Bar());
    }
}

@Service
class Sender {

    @Autowired
    private RabbitMessagingTemplate rabbitMessagingTemplate;
    @Autowired
    private MappingJackson2MessageConverter mappingJackson2MessageConverter;

    public void sendToRabbitmq(final Foo foo, final Bar bar) {

        this.rabbitMessagingTemplate.setMessageConverter(this.mappingJackson2MessageConverter);

        this.rabbitMessagingTemplate.convertAndSend("exchange", "queue", foo);
        this.rabbitMessagingTemplate.convertAndSend("exchange", "queue", bar);

    }
}

class Bar {
    public int age = 33;
}

class Foo {
    public String name = "gustavo";
}

消费者微服务

package demo.consumer;

import org.springframework.amqp.rabbit.annotation.EnableRabbit;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.stereotype.Service;

@SpringBootApplication
@EnableRabbit
public class ConsumerApplication implements CommandLineRunner {

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

    @Autowired
    private Receiver receiver;

    @Override
    public void run(String... args) throws Exception {

    }

}

@Service
class Receiver {
    @RabbitListener(queues = "queue")
    public void receiveMessage(Foo foo) {
        System.out.println("Received <" + foo.name + ">");
    }

    @RabbitListener(queues = "queue")
    public void receiveMessage(Bar bar) {
        System.out.println("Received <" + bar.age + ">");
    }
}

class Foo {
    public String name;
}

class Bar {
    public int age;
}

这是我得到的例外:

    org.springframework.amqp.rabbit.listener.exception.ListenerExecutionFailedException: Listener method could not be invoked with the incoming message
Endpoint handler details:
Method [public void demo.consumer.Receiver.receiveMessage(demo.consumer.Bar)]
Bean [demo.consumer.Receiver@1672fe87]
    at org.springframework.amqp.rabbit.listener.adapter.MessagingMessageListenerAdapter.invokeHandler(MessagingMessageListenerAdapter.java:116)
    at org.springframework.amqp.rabbit.listener.adapter.MessagingMessageListenerAdapter.onMessage(MessagingMessageListenerAdapter.java:93)
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:756)
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:679)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access$001(SimpleMessageListenerContainer.java:83)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$1.invokeListener(SimpleMessageListenerContainer.java:170)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.invokeListener(SimpleMessageListenerContainer.java:1257)
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.executeListener(AbstractMessageListenerContainer.java:660)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.doReceiveAndExecute(SimpleMessageListenerContainer.java:1021)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.receiveAndExecute(SimpleMessageListenerContainer.java:1005)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access$700(SimpleMessageListenerContainer.java:83)
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.run(SimpleMessageListenerContainer.java:1119)
    at java.lang.Thread.run(Thread.java:745)
Caused by: org.springframework.amqp.support.converter.MessageConversionException: Cannot handle message
    ... 13 common frames omitted
Caused by: org.springframework.messaging.converter.MessageConversionException: No converter found to convert to class demo.consumer.Bar, message=GenericMessage [payload=byte[10], headers={amqp_receivedRoutingKey=queue, amqp_receivedExchange=exchange, amqp_deliveryTag=1, amqp_deliveryMode=PERSISTENT, amqp_consumerQueue=queue, amqp_redelivered=false, id=87cf7e06-a78a-ddc1-71f5-c55066b46b11, amqp_consumerTag=amq.ctag-msWSwB4bYGWVO2diWSAHlw, contentType=application/json;charset=UTF-8, timestamp=1433989934574}]
    at org.springframework.messaging.handler.annotation.support.PayloadArgumentResolver.resolveArgument(PayloadArgumentResolver.java:115)
    at org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:77)
    at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:127)
    at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:100)
    at org.springframework.amqp.rabbit.listener.adapter.MessagingMessageListenerAdapter.invokeHandler(MessagingMessageListenerAdapter.java:113)
    ... 12 common frames omitted

异常说没有转换器，这是真的，我的问题是我不知道如何在消费者端设置MappingJackson2MessageConverter转换器(请注意我要使用org.springframework.messaging.converter.MappingJackson2MessageConverter 而不是 org.springframework.amqp.support.converter.JsonMessageConverter)

The exception says there is no converter, and that is true, my problem is that I have no idea how to set the MappingJackson2MessageConverter converter in the consumer side (please note that I want to use org.springframework.messaging.converter.MappingJackson2MessageConverter and not org.springframework.amqp.support.converter.JsonMessageConverter)

有什么想法吗?

以防万一，您可以在以下位置创建此示例项目:https://github.com/gustavoorsi/rabbitmq-consumer-receiver

Just in case, you can fork this sample project at: https://github.com/gustavoorsi/rabbitmq-consumer-receiver

推荐答案

好的，我终于搞定了.

Spring 使用 PayloadArgumentResolver 来提取、转换并将转换后的消息设置为使用 @RabbitListener 注释的方法参数.不知何故，我们需要将 ma​​ppingJackson2MessageConverter 设置到这个对象中.

Spring uses a PayloadArgumentResolver to extract, convert and set the converted message to the method parameter annotated with @RabbitListener. Somehow we need to set the mappingJackson2MessageConverter into this object.

因此，在 CONSUMER 应用中，我们需要实现 RabbitListenerConfigurer.通过重写 configureRabbitListeners(RabbitListenerEndpointRegistrar registrar) 我们可以设置一个自定义的 DefaultMessageHandlerMethodFactory，我们为这个工厂设置消息转换器，工厂将创建我们的 PayloadArgumentResolver 使用正确的转换.

So, in the CONSUMER app, we need to implement RabbitListenerConfigurer. By overriding configureRabbitListeners(RabbitListenerEndpointRegistrar registrar) we can set a custom DefaultMessageHandlerMethodFactory, to this factory we set the message converter, and the factory will create our PayloadArgumentResolver with the the correct convert.

这是代码片段，我还更新了 git 项目.

Here is a snippet of the code, I've also updated the git project.

ConsumerApplication.java 

package demo.consumer;

import org.springframework.amqp.rabbit.annotation.EnableRabbit;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.amqp.rabbit.annotation.RabbitListenerConfigurer;
import org.springframework.amqp.rabbit.listener.RabbitListenerEndpointRegistrar;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.messaging.converter.MappingJackson2MessageConverter;
import org.springframework.messaging.handler.annotation.support.DefaultMessageHandlerMethodFactory;
import org.springframework.stereotype.Service;

@SpringBootApplication
@EnableRabbit
public class ConsumerApplication implements RabbitListenerConfigurer {

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

    @Bean
    public MappingJackson2MessageConverter jackson2Converter() {
        MappingJackson2MessageConverter converter = new MappingJackson2MessageConverter();
        return converter;
    }

    @Bean
    public DefaultMessageHandlerMethodFactory myHandlerMethodFactory() {
        DefaultMessageHandlerMethodFactory factory = new DefaultMessageHandlerMethodFactory();
        factory.setMessageConverter(jackson2Converter());
        return factory;
    }

    @Override
    public void configureRabbitListeners(RabbitListenerEndpointRegistrar registrar) {
        registrar.setMessageHandlerMethodFactory(myHandlerMethodFactory());
    }

    @Autowired
    private Receiver receiver;

}

@Service
class Receiver {
    @RabbitListener(queues = "queue")
    public void receiveMessage(Foo foo) {
        System.out.println("Received <" + foo.name + ">");
    }

    @RabbitListener(queues = "queue")
    public void receiveMessage(Bar bar) {
        System.out.println("Received <" + bar.age + ">");
    }
}

class Foo {
    public String name;
}

class Bar {
    public int age;
}

因此，如果您运行 Producer 微服务，它将在队列中添加 2 条消息.一个代表 Foo 对象，另一个代表 Bar 对象.通过运行消费者微服务，您将看到两者都被 Receiver 类中的相应方法使用.

So, if you run the Producer microservice it will add 2 messages in the queue. One that represent a Foo object and another that represent a Bar object. By running the consumer microservice you will see that both are consumed by the respective method in the Receiver class.

更新问题:

我认为，我认为排队存在概念上的问题.通过声明 2 个用 @RabbitListener 注释的指向同一个队列的方法，我想要实现的目标是不可能的.上述解决方案无法正常工作.如果你发送到rabbitmq，比如说，6 条Foo 消息和3 条Bar 消息，它们不会被带有Foo 参数的监听器接收6 次.似乎侦听器是并行调用的，因此无法根据方法参数类型区分要调用的侦听器.我的解决方案(我不确定这是否是最好的方法，我在这里接受建议)是为每个实体创建一个队列.所以现在，我有 queue.bar 和 queue.foo，并更新 @RabbitListener(queues = "queue.foo")我再次更新了代码，您可以在我的 git 存储库中查看它.

There is a conceptual problem about queuing from my side I think. What I wanted to achieved can not be possible by declaring 2 methods annotated with @RabbitListener that points to the same queue. The solution above was not working properly. If you send to rabbitmq, let say, 6 Foo messages and 3 Bar messages, they wont be received 6 times by the listener with Foo parameter. It seems that the listener are invoked in parallel so there is no way to discriminate which listener to invoke based on the method argument type. My solution (and I'm not sure if this is the best way, I'm open to suggestions here) is to create a queue for each entity. So now, I have queue.bar and queue.foo, and update @RabbitListener(queues = "queue.foo") Once again, I've updated the code and you can check it out in my git repository.

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