MessageConversionException：无法在 Spring AMQP 中解析类名

Question

我正在尝试使用带有jackson2JsonMessageConverter. 另外，_TypeId_这里为什么显示带有类名的发件人包有什么意义？我在接收消息时遇到问题。

下面是我的配置

org.springframework.amqp.support.converter.MessageConversionException：无法解析类名。找不到类 [org.springframework.amqp.helloworld.User] 在 org.springframework.amqp.support.converter.DefaultJackson2JavaTypeMapper.getClassIdType(DefaultJackson2JavaTypeMapper.java:121) 在 org.springframework.amqp.support.converter.DefaultJackson2JavaTypeMapper.to DefaultJackson2JavaTypeMapper.java:90) 在 org.springframework.amqp.support.converter.Jackson2JsonMessageConverter.fromMessage(Jackson2JsonMessageConverter.java:145) 在 org.springframework.amqp.rabbit.listener.adapter.AbstractAdaptableMessageAbstractMessageAbstractMessage(3)在 org.springframework.amqp.rabbit.listener.adapter.MessageListenerAdapter。

XML 配置

            <?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
            xmlns:context="http://www.springframework.org/schema/context"
            xmlns:jdbc="http://www.springframework.org/schema/jdbc" xmlns:tx="http://www.springframework.org/schema/tx"
            xmlns:jpa="http://www.springframework.org/schema/data/jpa" xmlns:mvc="http://www.springframework.org/schema/mvc"
            xmlns:rabbit="http://www.springframework.org/schema/rabbit"
            xsi:schemaLocation="http://www.springframework.org/schema/rabbit
             http://www.springframework.org/schema/rabbit/spring-rabbit.xsd
             http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd  
             http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
             http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd  
             http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd  
             http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
             http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd">


            <rabbit:connection-factory id="connectionFactory"
                        channel-cache-size="25" host="10.165.18.29" username="BipUser"
                        password="bip" />

            <rabbit:queue name="Job Queue"></rabbit:queue>

            <rabbit:queue name="Input Queue"></rabbit:queue>

            <rabbit:queue name="More Info Queue"></rabbit:queue>

            <rabbit:queue name="Adaptor O/P Queue"></rabbit:queue>

            <rabbit:queue name="Command Queue"></rabbit:queue>

            <rabbit:queue name="Error Queue"></rabbit:queue>

            <bean id="simpleMessageConverter"
                        class="org.springframework.amqp.support.converter.Jackson2JsonMessageConverter">
            </bean>

            <rabbit:template id="amqpTemplate" connection-factory="connectionFactory"
                        message-converter="jsonConverterWithDefaultType" />

            <rabbit:listener-container
                        connection-factory="connectionFactory" auto-declare="true"
                        message-converter="simpleMessageConverter" auto-startup="true"
                        acknowledge="auto">
                        <rabbit:listener ref="rabbitMQJobListener"
                                    queue-names="Job Queue" priority="10" />

            </rabbit:listener-container>

            <rabbit:admin connection-factory="connectionFactory" id="amqpAdmin" />

            <bean id="rabbitMQJobListener" class="com.bosch.bip.rabbitmq.consumer.RabbitMQJobListener">
            </bean>

            <rabbit:annotation-driven container-factory="rabbitListenerContainerFactory" />

            <bean id="rabbitListenerContainerFactory"
                        class="org.springframework.amqp.rabbit.config.SimpleRabbitListenerContainerFactory">
                        <property name="connectionFactory" ref="connectionFactory"></property>
                        <property name="messageConverter" ref="jsonConverterWithDefaultType"></property>
            </bean>

            <bean id="jsonConverterWithDefaultType"
                        class="org.springframework.amqp.support.converter.Jackson2JsonMessageConverter">
                        <property name="classMapper">
                                    <bean class="org.springframework.amqp.support.converter.DefaultClassMapper">
                                    </bean>
                        </property>
            </bean>
</beans>

发件人

package org.springframework.amqp.helloworld;

import org.springframework.amqp.core.Message;
import org.springframework.amqp.core.MessageProperties;
import org.springframework.amqp.rabbit.core.RabbitTemplate;
import org.springframework.amqp.support.converter.DefaultClassMapper;
import org.springframework.amqp.support.converter.Jackson2JsonMessageConverter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.stereotype.Component;

@Component
public class Sender {


            public static void main(String[] args) {

                        ApplicationContext context = new AnnotationConfigApplicationContext(HelloWorldConfiguration.class);
                        User user=new User();
                        user.setPassword("welcome");
                        user.setUserName("welcome");
                        user.setXml("myxml");
                        RabbitTemplate rabbitTemplate = context.getBean(RabbitTemplate.class);

                        Jackson2JsonMessageConverter converter = context.getBean(Jackson2JsonMessageConverter.class);
                        MessageProperties properties = new MessageProperties();
                        properties.setHeader("user", "user");
                        properties.setContentType(MessageProperties.CONTENT_TYPE_JSON);
                        Message message = converter.toMessage(user, properties);

                        System.out.println(message);



                        rabbitTemplate.send(message);
            }

            /* @RabbitListener(queues = HelloWorldConfiguration.helloWorldQueueName)
              public void handleMessage(User user) {
               System.out.println("User Values::::::::"+user.getPassword());
              }*/
}

消费者

package com.bip.rabbitmq.consumer;

import org.springframework.amqp.rabbit.annotation.EnableRabbit;
import org.springframework.amqp.rabbit.annotation.RabbitListener;
import org.springframework.stereotype.Component;

import com.bip.entity.User;

@EnableRabbit
@Component
public class RabbitMQJobListener {


            @RabbitListener(queues="Job Queue")
            public void onMessage(User message) {
                        System.out.println(new String(message.getPassword()));

            }
}

兔MQ

Exchange    (AMQP default)
Routing Key Job Queue
Redelivered ?
Properties  
priority:   0
delivery_mode:  2
headers:    
user:   user
__TypeId__: org.springframework.amqp.helloworld.User
content_encoding:   UTF-8
content_type:   application/json
Payload
57 bytes
Encoding: string
{"userName":"welcome","password":"welcome","xml":"myxml"}

Answer 1

该_TypeID_头被设置在出站告诉入境什么类的JSON转换。如果要转换为与 JSON 类型兼容的其他类，则必须配置转换器。

如果它总是相同的类，请使用自定义ClassMapper（不是默认的）。

或者，看到这个测试，其监听器和它的配置，看看如何配置不同的typeid映射。

Answer 2

当序列化实例的包名称与消费者的模型（由标头 TypeId 表示）不同时，可能会发生这种情况。

我相信下面的例子会让事情变得更清楚。

架构：扇出类型的交换 x.invoice 绑定到队列 q.invoice。

生产者：我们正在发送类型 Id com.example. Produceronequeuemultipletypes.model.InvoiceCreatedMessage 的 JSON 消息。ParseConfig类是帮助我们避免手动将实例序列化为String。

public void sendInvoiceMessages() {
    invoiceCreatedMessage.setId(0);
    invoiceCreatedMessage.setType("Invoice Created");
    rabbitTemplate.convertAndSend("x.invoice", "", invoiceCreatedMessage);   
}

class InvoiceCreatedMessage {
    private String type;
    private int id;
}

@Configuration
class ParseConfig {
    @Bean
    public ObjectMapper getObjectMapper() {
        return new ObjectMapper();
    }

    @Bean
    public Jackson2JsonMessageConverter getConverter(
            @Autowired ObjectMapper objectMapper) {
        return new Jackson2JsonMessageConverter(objectMapper);
    }
}

消费者：创建一个类映射器 bean，映射从“com.example. Produceronequeuemultipletypes.model.InvoiceCreated”到 InvoiceCreated.class。

@Slf4j
@Service
public class InvoiceConsumer {
    @RabbitListener(queues = "q.invoice")
    public void handleInvoiceCreated(
            InvoiceCreatedMessage invoiceCreatedMessage) {
        log.info("[Created] Invoice " + invoiceCreatedMessage);
    }
}

@Configuration
class ParseConfig {
    @Bean
    public ObjectMapper getObjectMapper() {
        return new ObjectMapper();
    }

    @Bean
    public Jackson2JsonMessageConverter getConverter(
            @Autowired ObjectMapper objectMapper) {
        Jackson2JsonMessageConverter messageConverter =
        new Jackson2JsonMessageConverter(objectMapper);
        messageConverter.setClassMapper(getClassMapper());
        return messageConverter;
    }

    @Bean
    public DefaultClassMapper getClassMapper() {
        DefaultClassMapper classMapper = new DefaultClassMapper();
        Map<String, Class<?>> map = new HashMap<>();
        map.put(
        "com.example.produceronequeuemultipletypes.model." + 
        "InvoiceCreatedMessage",
        InvoiceCreatedMessage.class)
        classMapper.setIdClassMapping(idClassMapping);
        return classMapper;
    }
}

class InvoiceCreatedMessage {
    private String type;
    private int id;
}

参考：

1. https://docs.spring.io/spring-amqp/reference/html/#json-message-converter
2. https://www.udemy.com/course/rabbitmq-java-spring-boot-for-system-integration/