spring boot rabbitmq MappingJackson2MessageConverter自定义对象转换

Question

我正在尝试创建一个带弹簧启动的简单弹簧启动应用程序,它将"生成"消息发送到rabbitmq交换/队列以及另一个"消耗"这些消息的示例Spring启动应用程序.所以我有两个应用程序(或微服务,如果你愿意).1)"生产者"微服务2)"消费者"微服务

"生产者"有2个域对象.Foo和Bar应该转换为json并发送给rabbitmq."消费者"应该分别接收并将json消息转换为域Foo和Bar.出于某种原因,我不能完成这个简单的任务.关于这个的例子并不多.对于消息转换器我想使用org.springframework.messaging.converter.MappingJackson2MessageConverter

这是我到目前为止:

生产者MICROSERVICE

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";
}

消费者微软服务

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

例外情况说没有转换器,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(请注意我想使用org.springframework.messaging.converter.MappingJackson2MessageConverter而不是org.springframework.amqp.support.converter.JsonMessageConverter)

有什么想法吗 ？

为了以防万一,您可以在以下网址分享此示例项目:https: //github.com/gustavoorsi/rabbitmq-consumer-receiver

Answer 1

好的,我终于有了这个工作.

Spring使用PayloadArgumentResolver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mappingJackson2MessageConverter设置为此对象.

因此,在CONSUMER应用程序中,我们需要实现RabbitListenerConfigurer.通过重写configureRabbitListeners(RabbitListenerEndpointRegistrar注册器),我们可以设置一个自定义的DefaultMessageHandlerMethodFactory,我们在这个工厂设置了消息转换器,并且工厂将使用正确的转换创建我们的PayloadArgumentResolver.

这是代码片段,我还更新了git项目.

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.一个表示Foo对象,另一个表示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.

更新的问题:

我认为有一个关于从我这边排队的概念性问题.通过声明使用@RabbitListener注释的两个指向同一队列的方法,我无法实现我想要实现的目标.上述解决方案无法正常工作.如果你发送给rabbitmq,比如6个Foo消息和3个Bar消息,那么听众就不会用Foo参数接收6次.似乎并行调用了侦听器,因此无法根据方法参数类型区分调用哪个侦听器.我的解决方案(我不确定这是否是最好的方法,我愿意接受这里的建议)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,你可以在我的git存储库中查看它.