如何在Spring启动应用程序中使用spring-rabbit处理JSON消息？

时间：2017-02-28 09:28:50

标签： java spring spring-boot spring-amqp spring-rabbit

以下是我的代码段。

  • MQConfiguration用于配置的课程

    @Configuration
public class MQConfiguration {
    @Bean
    public Receiver receiver() {
        return new Receiver();
    }
}
    • 处理接收消息的

  • Receiver类

    @RabbitListener(queues = "testMQ")
public class Receiver {

    @RabbitHandler
    public void receive(Message msg){
        System.out.println(msg.toString());
    }
}

  • 以下是我发送给 RabbitMQ

    的JSON消息 
    {
    "id": 1,
    "name": "My Name",
    "description": "This is description about me"
}

但是，当我运行我的应用程序时，我收到了以下错误消息。

2017-02-28 17:16:35.931  WARN 11828 --- [cTaskExecutor-1] s.a.r.l.ConditionalRejectingErrorHandler : Execution of Rabbit message listener failed.

org.springframework.amqp.rabbit.listener.exception.ListenerExecutionFailedException: Listener threw exception
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.wrapToListenerExecutionFailedExceptionIfNeeded(AbstractMessageListenerContainer.java:872) ~[spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:782) ~[spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:702) ~[spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access$001(SimpleMessageListenerContainer.java:95) [spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$1.invokeListener(SimpleMessageListenerContainer.java:186) ~[spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.invokeListener(SimpleMessageListenerContainer.java:1227) [spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.executeListener(AbstractMessageListenerContainer.java:683) ~[spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.doReceiveAndExecute(SimpleMessageListenerContainer.java:1181) [spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.receiveAndExecute(SimpleMessageListenerContainer.java:1165) [spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access$1500(SimpleMessageListenerContainer.java:95) [spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.run(SimpleMessageListenerContainer.java:1367) [spring-rabbit-1.7.0.RELEASE.jar:na]
    at java.lang.Thread.run(Thread.java:745) [na:1.8.0_60]
Caused by: org.springframework.amqp.AmqpException: No method found for class [B
    at org.springframework.amqp.rabbit.listener.adapter.DelegatingInvocableHandler.getHandlerForPayload(DelegatingInvocableHandler.java:127) ~[spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.adapter.DelegatingInvocableHandler.getMethodNameFor(DelegatingInvocableHandler.java:224) ~[spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.adapter.HandlerAdapter.getMethodAsString(HandlerAdapter.java:61) ~[spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.adapter.MessagingMessageListenerAdapter.invokeHandler(MessagingMessageListenerAdapter.java:140) ~[spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.adapter.MessagingMessageListenerAdapter.onMessage(MessagingMessageListenerAdapter.java:106) ~[spring-rabbit-1.7.0.RELEASE.jar:na]
    at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:779) ~[spring-rabbit-1.7.0.RELEASE.jar:na]
    ... 10 common frames omitted

那么，如果我想要的是在receive()方法中打印JSON消息，我该怎么办？我真的很感激任何人都能对此有所了解。 ：）

4 个答案:

答案 0 :(得分：1)

如果您使用Spring Boot，则只需配置：

@Bean
public MessageConverter jsonMessageConverter() {
    return new Jackson2JsonMessageConverter();
}

否则你必须配置：

@Bean
public SimpleRabbitListenerContainerFactory rabbitListenerContainerFactory() {
    SimpleRabbitListenerContainerFactory factory = new SimpleRabbitListenerContainerFactory();
...
    factory.setMessageConverter(new Jackson2JsonMessageConverter());
...
    return factory;
}

http://docs.spring.io/spring-amqp/docs/1.7.0.RELEASE/reference/html/_reference.html#async-annotation-driven

答案 1 :(得分：1)

我知道距离上次回复已经有一段时间了，但我想添加我的答案。以防万一其他人遇到同样的问题。

当我设置像你这样的接收器时，我遇到了类似的问题，我无法将 RabbitMQ 消息正文中的 JSON 转换为我的对象。它只是返回一条这样的错误消息。

org.springframework.amqp.rabbit.support.ListenerExecutionFailedException: Failed to convert message
        at org.springframework.amqp.rabbit.listener.adapter.MessagingMessageListenerAdapter.onMessage(MessagingMessageListenerAdapter.java:146) ~[spring-rabbit-2.3.9.jar:2.3.9]
        at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doInvokeListener(AbstractMessageListenerContainer.java:1654) ~[spring-rabbit-2.3.9.jar:2.3.9]
        at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.actualInvokeListener(AbstractMessageListenerContainer.java:1573) ~[spring-rabbit-2.3.9.jar:2.3.9]
        at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.invokeListener(AbstractMessageListenerContainer.java:1561) ~[spring-rabbit-2.3.9.jar:2.3.9]
        at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.doExecuteListener(AbstractMessageListenerContainer.java:1552) ~[spring-rabbit-2.3.9.jar:2.3.9]
        at org.springframework.amqp.rabbit.listener.AbstractMessageListenerContainer.executeListener(AbstractMessageListenerContainer.java:1496) ~[spring-rabbit-2.3.9.jar:2.3.9]
        at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.doReceiveAndExecute(SimpleMessageListenerContainer.java:968) [spring-rabbit-2.3.9.jar:2.3.9]
        at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.receiveAndExecute(SimpleMessageListenerContainer.java:914) [spring-rabbit-2.3.9.jar:2.3.9]
        at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer.access$1600(SimpleMessageListenerContainer.java:83) [spring-rabbit-2.3.9.jar:2.3.9]
        at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.mainLoop(SimpleMessageListenerContainer.java:1289) [spring-rabbit-2.3.9.jar:2.3.9]
        at org.springframework.amqp.rabbit.listener.SimpleMessageListenerContainer$AsyncMessageProcessingConsumer.run(SimpleMessageListenerContainer.java:1195) [spring-rabbit-2.3.9.jar:2.3.9]
        at java.lang.Thread.run(Thread.java:748) [na:1.8.0_271]
Caused by: org.springframework.amqp.AmqpException: No method found for class java.util.LinkedHashMap
        at org.springframework.amqp.rabbit.listener.adapter.DelegatingInvocableHandler.getHandlerForPayload(DelegatingInvocableHandler.java:185) ~[spring-rabbit-2.3.9.jar:2.3.9]
        at org.springframework.amqp.rabbit.listener.adapter.DelegatingInvocableHandler.getMethodFor(DelegatingInvocableHandler.java:317) ~[spring-rabbit-2.3.9.jar:2.3.9]
        at org.springframework.amqp.rabbit.listener.adapter.HandlerAdapter.getMethodFor(HandlerAdapter.java:110) ~[spring-rabbit-2.3.9.jar:2.3.9]
        at org.springframework.amqp.rabbit.listener.adapter.MessagingMessageListenerAdapter.invokeHandlerAndProcessResult(MessagingMessageListenerAdapter.java:192) ~[spring-rabbit-2.3.9.jar:2.3.9]
        at org.springframework.amqp.rabbit.listener.adapter.MessagingMessageListenerAdapter.onMessage(MessagingMessageListenerAdapter.java:137) ~[spring-rabbit-2.3.9.jar:2.3.9]
        ... 11 common frames omitted

在不同的网站上搜索了几个小时没有任何好的答案后，我终于发现@RabbitListener 在课堂级别不起作用。但是，当您将其移至方法级别时，它可以正常工作。

所以，我删除了@RabbitHandler 并将@RabbitListener 移到了接收方法中。

您的接收器代码在编辑后应如下所示。

public class Receiver {

    @RabbitListener(queues = "testMQ")
    public void receive(Message msg){
        System.out.println(msg.toString());
    }
}

我仍然不完全理解为什么它在类级别不起作用。如果有人有好的解释，请在评论部分分享。非常感谢。

来源：https://titanwolf.org/Network/Articles/Article?AID=0f214d79-10f0-4b4c-9478-607428770256#gsc.tab=0

答案 2 :(得分：0)

为了将JSON发送到RabbitMQ并通过Spring Boot使用它，我们需要设置content_type。

让我用一个示例来描述我有一个Python Producer和Java使用者（我将JSON从Python发送到RabbitMQ，Spring Boot Java应该接收JSON任务）。

有两种解决方案：

解决方案1：发送为JSON字符串并使用Jakson或GSON手动转换

您需要设置content_type =“text / plain”并将JSON转换为字符串。然后在Spring端，使用带有字符串的函数作为侦听器的输入并手动转换对象。

RabbitHandler：

@RabbitHandler
public void receive(String inputString) throws IOException {
    ObjectMapper objectMapper = new ObjectMapper();
    SimStatusReport theResult = objectMapper.readValue(inputString, SimStatusReport.class);

    System.out.println("String instance "  + theResult.toString() +
            " [x] Received");
}

SimStatusReport对象：

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class SimStatusReport {
    private String id;
    private int t;
}

这是我的Python代码：

import pika
import json
import uuid


connectionResult = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
channelResult = connectionResult.channel()
routing_key_result = 'sim_results'
channelResult.queue_declare(queue=routing_key_result, durable=True)

def publish_result(sim_status):
    message =json.dumps(sim_status)
    channelResult.basic_publish(exchange='',
                                routing_key=routing_key_result,
                                body=message,
                                properties=pika.BasicProperties(
                                    content_type="text/plain",
                                    content_encoding= 'UTF-8',
                                    delivery_mode=2,  # make message persistent
                          ))
    print("Sent ", message)


newsim_status = {'id': str(uuid.uuid4()), 't': 0}
publish_result(newsim_status)

解决方案2：发送JSON字符串并让Jackson2JsonMessageConverter自动为您进行转换。

您需要设置content_type =“application / json”。然后，您需要在RabbitMQ请求的标头中将适当的标头添加到__TypeId__。您需要包含对象的确切名称空间，以便杰克逊不会转换。

以下是使用Python的示例（只是publish_result功能）：

def publish_result(sim_status):
    message =json.dumps(sim_status)
    channelResult.basic_publish(exchange='',
                                routing_key=routing_key_result,
                                body=message,
                                properties=pika.BasicProperties(
                                    content_type="application/json"
                                    headers={'__TypeId__': 'com.zarinbal.simtest.run.model.SimStatusReport'},
                                    content_encoding= 'UTF-8',
                                    delivery_mode=2,  # make message persistent
                          ))
    print("Sent ", message)

然后您需要配置Java以使用Jackson2JsonMessageConverter：

@Configuration
    public class RabbitConfiguration {
        @Bean
        public MessageConverter jsonMessageConverter() {
            return new Jackson2JsonMessageConverter();
        }
    }

这是你的倾听者：

@RabbitListener(queues = "sim_results")
public class TaskReceiver {
    @RabbitHandler
    public void receive(SimStatusReport in) {
        System.out.println("Object instance "  + in +
                " [x] Received");
    }
}

注意： 确保所有对象都具有所有属性和所有参数构造函数的setter和getter。我使用来自lombok的@ Data，@ NoArgsConstructor和@AllArgsConstructor自动生成它

答案 3 :(得分：0)

以简单的方式可以使用此功能new String(Messages) 

@RabbitListener(queues = "testMQ")
public class Receiver {

    @RabbitHandler
    public void receive(Message msg){
String MQMessage = new String(msg.getBody());
        System.out.println(MQMessage);
    }
}
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