Programmatic Construction
此功能专为与 @KafkaListener
一起使用而设计;然而,一些用户已请求有关如何以编程方式配置非阻塞重试的信息。以下 Spring Boot 应用程序提供了有关如何执行此操作的示例。
@SpringBootApplication
public class Application extends RetryTopicConfigurationSupport {
public static void main(String[] args) {
SpringApplication.run(Application.class, args);
}
@Bean
RetryTopicConfiguration retryConfig(KafkaTemplate<String, String> template) {
return RetryTopicConfigurationBuilder.newInstance()
.maxAttempts(4)
.autoCreateTopicsWith(2, (short) 1)
.create(template);
}
@Bean
TaskScheduler scheduler() {
return new ThreadPoolTaskScheduler();
}
@Bean
@Order(0)
SmartInitializingSingleton dynamicRetry(RetryTopicConfigurer configurer, RetryTopicConfiguration config,
KafkaListenerAnnotationBeanPostProcessor<?, ?> bpp, KafkaListenerContainerFactory<?> factory,
Listener listener, KafkaListenerEndpointRegistry registry) {
return () -> {
KafkaListenerEndpointRegistrar registrar = bpp.getEndpointRegistrar();
MethodKafkaListenerEndpoint<String, String> mainEndpoint = new MethodKafkaListenerEndpoint<>();
EndpointProcessor endpointProcessor = endpoint -> {
// customize as needed (e.g. apply attributes to retry endpoints).
if (!endpoint.equals(mainEndpoint)) {
endpoint.setConcurrency(1);
}
// these are required
endpoint.setMessageHandlerMethodFactory(bpp.getMessageHandlerMethodFactory());
endpoint.setTopics("topic");
endpoint.setId("id");
endpoint.setGroupId("group");
};
mainEndpoint.setBean(listener);
try {
mainEndpoint.setMethod(Listener.class.getDeclaredMethod("onMessage", ConsumerRecord.class));
}
catch (NoSuchMethodException | SecurityException ex) {
throw new IllegalStateException(ex);
}
mainEndpoint.setConcurrency(2);
mainEndpoint.setTopics("topic");
mainEndpoint.setId("id");
mainEndpoint.setGroupId("group");
configurer.processMainAndRetryListeners(endpointProcessor, mainEndpoint, config, registrar, factory,
"kafkaListenerContainerFactory");
};
}
@Bean
ApplicationRunner runner(KafkaTemplate<String, String> template) {
return args -> {
template.send("topic", "test");
};
}
}
@Component
class Listener implements MessageListener<String, String> {
@Override
public void onMessage(ConsumerRecord<String, String> record) {
System.out.println(KafkaUtils.format(record));
throw new RuntimeException("test");
}
}
仅当在刷新应用程序上下文之前处理配置时,才会自动创建主题,如上面的示例所示。要在运行时配置容器,则需要使用其他技术创建主题。