告诉 Jackson2JsonMessageConverter 在 Amqp.inboundAdapter 中使用我自己的类答案

【问题标题】：Tell Jackson2JsonMessageConverter to use my own class in Amqp.inboundAdapter告诉 Jackson2JsonMessageConverter 在 Amqp.inboundAdapter 中使用我自己的类
【发布时间】：2020-10-06 20:18:19
【问题描述】：

鉴于我有 IntegrationFlow 和 AMQP 队列的入站适配器：

@Bean
public IntegrationFlow readMessagesFlow(
        ConnectionFactory rabbitConnectionFactory,
        ObjectMapper jacksonObjectMapper) {
    return IntegrationFlows.from(
            Amqp.inboundAdapter(rabbitConnectionFactory, QUEUE)
                    .messageConverter(new Jackson2JsonMessageConverter(jacksonObjectMapper))
    )
            .log(INFO, AMQP_LOGGER_CATEGORY)
            .get();
}

当某些外部系统发送带有 JSON 正文的消息时，我发现他们使用 __TypeId__=THEIR_INTERNAL_CLASS。

我想将 JSON 正文映射到我自己的类。

目前，它在ClassCastException 上失败，因为THEIR_INTERNAL_CLASS 不可用。

我如何告诉Jackson2JsonMessageConverter 使用我自己的类？

【问题讨论】：

标签： spring-integration spring-amqp spring-integration-dsl spring-integration-amqp

【解决方案1】：

看这个转换器的方法：

/**
 * Set the precedence for evaluating type information in message properties.
 * When using {@code @RabbitListener} at the method level, the framework attempts
 * to determine the target type for payload conversion from the method signature.
 * If so, this type is provided in the
 * {@link MessageProperties#getInferredArgumentType() inferredArgumentType}
 * message property.
 * <p> By default, if the type is concrete (not abstract, not an interface), this will
 * be used ahead of type information provided in the {@code __TypeId__} and
 * associated headers provided by the sender.
 * <p> If you wish to force the use of the  {@code __TypeId__} and associated headers
 * (such as when the actual type is a subclass of the method argument type),
 * set the precedence to {@link Jackson2JavaTypeMapper.TypePrecedence#TYPE_ID}.
 * @param typePrecedence the precedence.
 * @see DefaultJackson2JavaTypeMapper#setTypePrecedence(Jackson2JavaTypeMapper.TypePrecedence)
 */
public void setTypePrecedence(Jackson2JavaTypeMapper.TypePrecedence typePrecedence) {

这里是关于此事的文档：https://docs.spring.io/spring-amqp/docs/2.2.11.RELEASE/reference/html/#json-message-converter

【讨论】：

【解决方案2】：

这是一种方法：

Jackson2JsonMessageConverter messageConverter = new Jackson2JsonMessageConverter(jacksonObjectMapper);
DefaultClassMapper defaultClassMapper = new DefaultClassMapper();
defaultClassMapper.setDefaultType(MyOwnClass.class);
messageConverter.setClassMapper(defaultClassMapper);

在Amqp.inboundAdapter中使用messageConverter

【讨论】：