问题1

错误信息：

java.lang.IllegalArgumentException: SimpleMessageConverter only supports String, byte[] and Serializable payloads, received: com.hmall.api.dto.CartRemoveDTO

错误信息提示：RabbitMQ默认的消息转换器SimpleMessageConverter 无法对自定义对象生效；
解决方法：
让自定义对象实现Serializable接口，并配置消息转换器，生产者方和消费者方都要配置，如下所示：

java">    @Beanpublic MessageConverter messageConverter(){return new Jackson2JsonMessageConverter();}

问题2

错误信息：

Caused by: com.fasterxml.jackson.databind.exc.InvalidDefinitionException: Cannot construct instance of `com.hmall.api.dto.CartClearDTO` (no Creators, like default constructor, exist): cannot deserialize from Object value (no delegate- or property-based Creator)at [Source: (String)"{"userId":1,"itemIds":[1533902]}"; line: 1, column: 2]at com.fasterxml.jackson.databind.exc.InvalidDefinitionException.from(InvalidDefinitionException.java:67) ~[jackson-databind-2.13.5.jar:2.13.5]at com.fasterxml.jackson.databind.DeserializationContext.reportBadDefinition(DeserializationContext.java:1904) ~[jackson-databind-2.13.5.jar:2.13.5]at com.fasterxml.jackson.databind.DatabindContext.reportBadDefinition(DatabindContext.java:400) ~[jackson-databind-2.13.5.jar:2.13.5]at com.fasterxml.jackson.databind.DeserializationContext.handleMissingInstantiator(DeserializationContext.java:1349) ~[jackson-databind-2.13.5.jar:2.13.5]at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.deserializeFromObjectUsingNonDefault(BeanDeserializerBase.java:1415) ~[jackson-databind-2.13.5.jar:2.13.5]at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserializeFromObject(BeanDeserializer.java:352) ~[jackson-databind-2.13.5.jar:2.13.5]at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:185) ~[jackson-databind-2.13.5.jar:2.13.5]at com.fasterxml.jackson.databind.deser.DefaultDeserializationContext.readRootValue(DefaultDeserializationContext.java:323) ~[jackson-databind-2.13.5.jar:2.13.5]at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4674) ~[jackson-databind-2.13.5.jar:2.13.5]at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3629) ~[jackson-databind-2.13.5.jar:2.13.5]

错误提示在jackson方式反序列化时出现了错误，查阅得知，自定义对象只添加了@Data注解，而jackson的反序列化需要无参构造函数，
解决方法：
给自定义对象添加@NoArgsConstructor注解或者配置无参构造器。

参考链接：Jackson反序列化报错