Unable to autowire the Processor after adding User-defined message converters - apache-kafka

Question

On Finchley.SR2, here is the code
#Configuration
#EnableAutoConfiguration
#SpringBootApplication
#EnableBinding(Processor.class)
#RestController
public class Application {
private static Logger log = LoggerFactory.getLogger(Application.class);
#Autowired
private Processor processor;
#Autowired
MappingJackson2MessageConverter testConverter;
#Bean
#StreamMessageConverter
MappingJackson2MessageConverter createTestConverter(){
return new MappingJackson2MessageConverter();
}
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
}
When I start up, I got
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'org.springframework.cloud.stream.messaging.Processor' available: expected at least 1 bean which qualifies as autowire candidate. Dependency annotations: {#org.springframework.beans.factory.annotation.Autowired(required=true)}
But if I take out #StreamMessageConverter, the Processor can be autowired successfully.
What should I do to keep my customized message converter and autowired Processor at the same time? Thanks!

Answer 1

There is a lot going on there, so lets try to parse it put. . .
First question, why do you need to autowire the following?
#Autowired
private Processor processor;
You, generally don't need to interact with Processor directly since it is used bt the framework to provide a delegation/connectivity model between remote destinations exposed by the binders and your message handlers
Further more, your actual issue is related to a lifecycle which may be a minor yet harmless bug on our end and probably relates to configuring and autowiring Processor in the same configuration class.
Second:
#Configuration
#EnableAutoConfiguration
#SpringBootApplication
You only need one
#SpringBootApplication
Third:
Why do you need to configure MappingJackson2MessageConverter? Content type conversion is a transparent feature of he framework and while we do provide an ability to configure custom message converters, the one you are configuring is already configured by the framework and in fact is the first in the stack of seven pre-configured message converters
The final question:
What is it that your are trying to do? Can you explain your use case?