How to provide a custom deserializer with Jackson and Spring Boot

Firstly, you need to create your custom DynamoDemoEntityDeserializer like below:

class DynamoDemoEntityDeserializer extends JsonDeserializer<DynamoDemoEntity> {
    @Override
    public DynamoDemoEntity deserialize(JsonParser p, DeserializationContext ctxt)
                throws IOException, JsonProcessingException {
       // return DynamoDemoEntity instance;
    }
}

Then you can create bean of com.fasterxml.jackson.databind.Module like below:

@Bean
public Module dynamoDemoEntityDeserializer() {
    SimpleModule module = new SimpleModule();
    module.addDeserializer(IDemoEntity.class, new DynamoDemoEntityDeserializer());
    return module;
}

Any beans of type com.fasterxml.jackson.databind.Module are automatically registered with the auto-configured Jackson2ObjectMapperBuilder and are applied to any ObjectMapper instances that it creates. This provides a global mechanism for contributing custom modules when you add new features to your application.

Source: howto-customize-the-jackson-objectmapper