Question

当我尝试使用SQS消息时，我看到以下异常：

org.springframework.messaging.converter.MessageConversionException: 

Cannot convert from [java.lang.String] to [com.example.demo.Foo] for GenericMessage [payload={}, headers={LogicalResourceId=my-queue, ApproximateReceiveCount=1, SentTimestamp=1529021258825, ReceiptHandle=xxxx, Visibility=org.springframework.cloud.aws.messaging.listener.QueueMessageVisibility@47ce6922, SenderId=xxxx, lookupDestination=my-queue, ApproximateFirstReceiveTimestamp=1529021264456, MessageId=xxxx}]
    at org.springframework.messaging.handler.annotation.support.PayloadArgumentResolver.resolveArgument(PayloadArgumentResolver.java:144)
    at org.springframework.messaging.handler.invocation.HandlerMethodArgumentResolverComposite.resolveArgument(HandlerMethodArgumentResolverComposite.java:116)
    at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.getMethodArgumentValues(InvocableHandlerMethod.java:137)
    at org.springframework.messaging.handler.invocation.InvocableHandlerMethod.invoke(InvocableHandlerMethod.java:109)
    at org.springframework.messaging.handler.invocation.AbstractMethodMessageHandler.handleMatch(AbstractMethodMessageHandler.java:515)
    at org.springframework.messaging.handler.invocation.AbstractMethodMessageHandler.handleMessageInternal(AbstractMethodMessageHandler.java:473)
    at org.springframework.messaging.handler.invocation.AbstractMethodMessageHandler.handleMessage(AbstractMethodMessageHandler.java:409)
    at org.springframework.cloud.aws.messaging.listener.SimpleMessageListenerContainer.executeMessage(SimpleMessageListenerContainer.java:205)
    at org.springframework.cloud.aws.messaging.listener.SimpleMessageListenerContainer$MessageExecutor.run(SimpleMessageListenerContainer.java:342)
    at org.springframework.cloud.aws.messaging.listener.SimpleMessageListenerContainer$SignalExecutingRunnable.run(SimpleMessageListenerContainer.java:397)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

Spring Boot代码如下：

@Configuration
@EnableSqs
public class AmazonSqsConfiguration {

    @Bean
    public AmazonSQS amazonSQSAsync() {
        return AmazonSQSAsyncClientBuilder.standard()
            .withRegion(Regions.US_WEST_2)
            .build();
    }
}

@Service
public class MyService {

    // Throws MessageConversionException
    @SqsListener("my-queue")
    public void listen(Foo payload) {

    }

    // Works fine
    @SqsListener("my-queue")
    public void listen(String payload) {

    }
}

我正在使用org.springframework.cloud:spring-cloud-aws-messaging:2.0.0.RC2

我的类路径上有Jackson 2库，因此PayloadArgumentResolver正在尝试使用MappingJackson2MessageConverter反序列化我的消息有效负载。但是，由于缺少contentType标头的SQS消息，并且strictContentTypeMatch设置为true，canConvertFrom将返回false。

https://github.com/spring-projects/spring-framework/blob/f5e8f4983f7653169f3da8a3287499fce93cadd4/spring-messaging/src/main/java/org/springframework/messaging/converter/AbstractMessageConverter.java#L237

我看不出如何为SQS消息设置contentType标头 - 我错过了什么？

Spring Cloud QueueMessageHandler是否应将strictContentTypeMatch设置为true？

https://github.com/spring-cloud/spring-cloud-aws/blob/6a7c3c31709d4239131b27936de29385df414d41/spring-cloud-aws-messaging/src/main/java/org/springframework/cloud/aws/messaging/listener/QueueMessageHandler.java#L217

Answer 1

遇到同样的问题，我会根据是谁生成消息来回答以下两种方式之一的问题

是的，可以在消息上设置contentType，并且如果您控制正在生成的消息，则这是首选。在AWS控制台中，当您手动发送消息时，会有一个“消息属性”选项卡。您将添加一个名称为contentType且值为application/json的属性。 AWS SDK调用应允许您从应用程序代码执行相同的操作。
对于AWS生成的没有内容指定内容类型的消息，例如S3事件，实际上您确实需要将strictContentMatch设置为false。在此处记录： http://cloud.spring.io/spring-cloud-static/spring-cloud-aws/2.0.0.RELEASE/multi/multi__messaging.html#_consuming_aws_event_messages_with_amazon_sqs

文档令人困惑，因为它说“没有mime类型的标题”，但是标题的实际名称是contentType，就像您发现的那样。

Answer 2

在“发送”和“监听”方法中都具有一致的转换器：

/** Provides a deserialization template for incoming SQS messages */
@Bean
public QueueMessageHandlerFactory queueMessageHandlerFactory(MessageConverter messageConverter) {

    var factory = new QueueMessageHandlerFactory();
    factory.setArgumentResolvers(singletonList(new PayloadArgumentResolver(messageConverter)));
    return factory;
}

/** Provides a serialization template for outgoing SQS messages */
@Bean
public QueueMessagingTemplate queueMessagingTemplate(AmazonSQSAsync amazonSQSAsync, MessageConverter messageConverter) {
    return new QueueMessagingTemplate(amazonSQSAsync, (ResourceIdResolver) null, messageConverter);
}

/** Provides JSON converter for SQS messages */
@Bean
protected MessageConverter messageConverter(ObjectMapper objectMapper) {

  var converter = new MappingJackson2MessageConverter();
  converter.setObjectMapper(objectMapper);
  // Serialization support:
  converter.setSerializedPayloadClass(String.class);
  // Deserialization support: (suppress "contentType=application/json" header requirement)
  converter.setStrictContentTypeMatch(false);
  return converter;
}

在原始接受的答案中查看详细信息。归功于@wrschneider。

注意：上面的示例注入并设置了ObjectMapper。这是可选的，以确保HTTP REST控制器的一致性。

进口：

import static java.util.Collections.singletonList;

import com.amazonaws.services.sqs.AmazonSQSAsync;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.cloud.aws.core.env.ResourceIdResolver;
import org.springframework.cloud.aws.messaging.config.QueueMessageHandlerFactory;
import org.springframework.cloud.aws.messaging.core.QueueMessagingTemplate;
import org.springframework.context.annotation.Bean;
import org.springframework.messaging.converter.MappingJackson2MessageConverter;
import org.springframework.messaging.converter.MessageConverter;
import org.springframework.messaging.handler.annotation.support.PayloadArgumentResolver;

用法：

  @SqsListener("my-queue")
  public void listen(Foo payload) {

  }

  public void send(Foo dto) {
    queueMessagingTemplate.convertAndSend(url, dto);
  }

Spring Cloud @SqsListener MessageConversionException：无法从[java.lang.String]转换为GenericMessage

2 个答案: