我正在尝试使用Spring Boot创建一个简单的Spring Boot应用程序，该应用程序可以“生成”到Rabbitmq交换/队列的消息，而另一个示例Spring Boot应用程序可以“使用”这些消息。因此，我有两个应用程序（如果需要，也可以提供微服务）。1）“生产者”微服务2）“消费者”微服务
“生产者”具有2个域对象。Foo和Bar，应将其转换为json并发送给rabbitmq。“消费者”应接收并将json消息分别转换为Foo和Bar域。由于某些原因，我无法完成此简单任务。关于这个的例子不多。对于消息转换器，我想使用org.springframework.messaging.converter.MappingJackson2MessageConverter
这是我到目前为止的内容：
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
异常表示没有转换器，是的，我的问题是我不知道如何在使用者端设置 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，您可以在以下位置分叉该示例项目：https : //github.com/gustavoorsi/rabbitmq-consumer- receiver
好的，我终于可以工作了。
Spring使用 PayloadArgumentResolver 提取，转换并将转换后的消息设置为以 @RabbitListener 注释的方法参数。我们需要以某种方式将 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 registrar）， 我们可以将自定义 DefaultMessageHandlerMethodFactory 设置为该工厂，从而设置消息转换器，并且工厂将使用正确的转换来创建 PaypayArgumentResolver 。
这是代码片段，我还更新了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。通过运行使用者微服务，您将看到两者都被 Receiver 类中的相应方法所消耗。
更新的问题：
我认为从我这边排队有一个概念上的问题。我想实现的目标无法通过声明2个用 @RabbitListener 注释的方法指向同一队列来实现。上面的解决方案无法正常工作。如果您发送给rabbitmq，比如说6条Foo消息和3条Bar消息，则带有Foo参数的侦听器将不会收到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来区分要调用的侦听器。我的解决方案（而且我不确定这是否是最好的方法，在这里我可以提出建议）是为每个实体创建一个队列。所以现在，我有了 queue.bar 和 queue.foo ，并更新 @RabbitListener（queues =“ queue.foo”） 再一次，我更新了代码，您可以在git仓库中检出代码。
