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在 XD 流中，消息通过源模块从 Kafka 主题消费，然后发送到接收器 Kafka 模块。开发自定义源和接收器 Kafka 模块背后的原因是，我只想在成功发送消息时从下游接收器模块得到确认时更新源模块的偏移量。

我正在使用 Spring Integration Kafka 2.0.1.RELEASE 和 Spring Kafka 1.0.3.RELEASE 以及 Kafka 0.10.0.0 环境中的主题。我尝试了以下方法：

源模块配置：

@Configuration
public class ModuleConfiguration {

    @Value("${topic}")
    private String topic;

    @Value("${brokerList}")
    private String brokerAddress;

    @Bean
    public SubscribableChannel output() {
        DirectChannel output = new DirectChannel();
        return output;
    }

    @Autowired
    TopicPartitionInitialOffset topicPartition;

    @Bean
    public TopicPartitionInitialOffset topicPartition(){
        return new TopicPartitionInitialOffset(this.topic, 0, (long) 0);    
    }

    @Bean
    public KafkaMessageListenerContainer<String, String> container() throws Exception {
        ContainerProperties containerProps = new ContainerProperties(topicPartition);
        containerProps.setAckMode(AckMode.MANUAL);
        KafkaMessageListenerContainer<String, String> kafkaMessageListenerContainer = new KafkaMessageListenerContainer<>(consumerFactory(),containerProps);
        return kafkaMessageListenerContainer;
    }
    @Bean
    public ConsumerFactory<String, String> consumerFactory() {
        Map<String, Object> props = new HashMap<>();
        props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, this.brokerAddress);
        props.put(ConsumerConfig.GROUP_ID_CONFIG, "test-consumer-group");
        props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, false);
        props.put(ConsumerConfig.SESSION_TIMEOUT_MS_CONFIG, 15000);
        props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
        DefaultKafkaConsumerFactory<String,String> consumerFactory =  new DefaultKafkaConsumerFactory<>(props);
        return consumerFactory;
    }
}

源模块：InboundKafkaMessageDrivenAdapter

@MessageEndpoint
@Import(ModuleConfiguration.class)
public class InboundKafkaMessageDrivenAdapter {

    @Autowired
    KafkaMessageListenerContainer<String, String> container;

    @Autowired
    SubscribableChannel output;

    @Bean
    public KafkaMessageDrivenChannelAdapter<String, String> adapter(KafkaMessageListenerContainer<String, String> container) {
        KafkaMessageDrivenChannelAdapter<String, String> kafkaMessageDrivenChannelAdapter = new KafkaMessageDrivenChannelAdapter<>(container);
        kafkaMessageDrivenChannelAdapter.setOutputChannel(output);
        return kafkaMessageDrivenChannelAdapter;
    }
}

接收器模块：配置

@Configuration
@EnableIntegration
public class ModuleConfiguration {

    @Value("${topic}")
    private String topic;

    @Value("${brokerList}")
    private String brokerAddress;

    @Bean
    public KafkaProducerMessageHandler<String,String> handler() throws Exception {
        KafkaProducerMessageHandler<String, String> handler = new KafkaProducerMessageHandler<>(kafkaTemplate());
        handler.setTopicExpression(new LiteralExpression(this.topic));
        return handler;
    }

    @Bean
    public SubscribableChannel input() {
        return new DirectChannel();
    }

    @Bean
    public KafkaTemplate<String, String> kafkaTemplate() {
        return new KafkaTemplate<>(producerFactory());
    }

    @Bean
    public ProducerFactory<String, String> producerFactory() {
        Map<String, Object> props = new HashMap<>();
        props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, this.brokerAddress);
        props.put(ProducerConfig.RETRIES_CONFIG, 0);
        props.put(ProducerConfig.BATCH_SIZE_CONFIG, 16384);
        props.put(ProducerConfig.LINGER_MS_CONFIG, 1);
        props.put(ProducerConfig.BUFFER_MEMORY_CONFIG, 33554432);
        props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
        props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
        return new DefaultKafkaProducerFactory<>(props);
    }
}

接收器模块：SinkActivator

@Import(ModuleConfiguration.class)
@MessageEndpoint
public class SinkActivator {

    @Autowired
    KafkaProducerMessageHandler<String,String> handler;

    @Autowired
    SubscribableChannel input;

    @ServiceActivator(inputChannel = "input")
    public void sendMessage(Message<?> msg) throws Exception{
            Acknowledgment acknowledgment = msg.getHeaders().get(KafkaHeaders.ACKNOWLEDGMENT, Acknowledgment.class);
            handler.handleMessage(msg);
            acknowledgment.acknowledge();
            }
}

源成功接收消息并将它们发送到接收器，但是当我尝试在接收器中获取确认时：

确认确认 = msg.getHeaders().get(KafkaHeaders.ACKNOWLEDGMENT, Acknowledgment.class);

抛出以下异常：

原因：java.lang.IllegalArgumentException：为标头“kafka_acknowledgment”指定的类型不正确。预期 [interface org.springframework.kafka.support.Acknowledgment] 但实际类型是 [class org.springframework.kafka.listener.KafkaMessageListenerContainer$ListenerConsumer$ConsumerAcknowledgment]

在 spring-integration-kafka-2.0.1.RELEASE 的源代码中，当 AckMode=MANUAL 时，KafkaMessageListenerContainer 类将 kafka_acknowledgment 标头添加到消息中，但是类型是 ConsumerAcknowldgment 的内部静态类。

那么如何从源发送的消息上从接收模块获得确认？

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1 回答 1

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除非您使用本地传输，否则您不能这样做，这Acknowledgment是一个“活动”对象，不能通过线路发送到另一个模块。

如果您使用本地传输，它会工作，但您会遇到类加载器问题，因为每个模块都在其自己的类加载器中运行，并且Acknowledgment接口是类的不同实例。

您必须将 spring-integration-kafka 和 spring-kafka 移动到 xd/lib 文件夹，以便从通用类加载器加载类。

于 2016-08-19T16:11:13.093 回答