Question

我正在使用Kafka 0.8.0并试图实现下面提到的场景。

JCA API（充当生产者并向其发送数据）-----＆gt;消费者------＆GT; HBase的

我在使用JCA客户端获取数据后立即将每条消息发送给消费者。例如，一旦生产者发送消息no.1，我想从消费者那里获取相同的内容并在HBase中“put”。但是我的消费者在一些随机的n消息之后开始获取消息。我想让生产者和消费者同步，以便他们两个开始一起工作。

我用过：

1经纪人

1个单一主题

1个单一生产者和高级消费者

任何人都可以建议我需要做些什么来实现同样的目标？

编辑：

添加一些相关的代码段。

Consumer.java

public class Consumer extends Thread {
    private final ConsumerConnector consumer;
    private final String topic;
    PrintWriter pw = null;
    int t = 0;
    StringDecoder kd = new StringDecoder(null);
    Map<String, Integer> topicCountMap = new HashMap<String, Integer>();
    Map<String, List<KafkaStream<String, Signal>>> consumerMap;
    KafkaStream<String, Signal> stream;
    ConsumerIterator<String, Signal> it;

    public Consumer(String topic) {
        consumer = kafka.consumer.Consumer.createJavaConsumerConnector(createConsumerConfig());

        this.topic = topic;
        topicCountMap.put(topic, new Integer(1));
        consumerMap = consumer.createMessageStreams(topicCountMap, kd, new Serializer(
                new VerifiableProperties()));
        stream = consumerMap.get(topic).get(0);
        it = stream.iterator();

    }

    private static ConsumerConfig createConsumerConfig() {
        Properties props = new Properties();
        props.put("zookeeper.connect", KafkaProperties.zkConnect);
        props.put("group.id", KafkaProperties.groupId);
        props.put("zookeeper.session.timeout.ms", "400");
        props.put("zookeeper.sync.time.ms", "200");
        props.put("auto.commit.interval.ms", "1000");
        props.put("fetch.size", "1024");

        return new ConsumerConfig(props);

    }

    synchronized public void run() {

        while (it.hasNext()) {
            t = (it.next().message()).getChannelid();
            System.out.println("In Consumer received msg" + t);
        }
    }
}

producer.java

public class Producer {
    public final kafka.javaapi.producer.Producer<String, Signal> producer;
    private final String topic;
    private final Properties props = new Properties();

    public Producer(String topic)
    {
        props.put("serializer.class", "org.bigdata.kafka.Serializer");
        props.put("key.serializer.class", "kafka.serializer.StringEncoder");
        props.put("metadata.broker.list", "localhost:9092");
        // Use random partitioner. Don't need the key type. Just set it to Integer.
        // The message is of type userdefined Object .
        producer = new kafka.javaapi.producer.Producer<String,Signal(newProducerConfig(props));
        this.topic = topic;
    }
}

KafkaProperties.java

public interface KafkaProperties {
    final static String zkConnect = "127.0.0.1:2181";
    final static String groupId = "group1";
    final static String topic = "test00";
    final static String kafkaServerURL = "localhost";
    final static int kafkaServerPort = 9092;
    final static int kafkaProducerBufferSize = 64 * 1024;
    final static int connectionTimeOut = 100000;
    final static int reconnectInterval = 10000;
    final static String clientId = "SimpleConsumerDemoClient";
}

这是消费者对前10条消息的行为方式，它不会消费消费者收到的消息，但从第11条消息开始，它开始正常运作。

     producer sending msg1

     producer sending msg2

     producer sending msg3

     producer sending msg4

     producer sending msg5

     producer sending msg6

     producer sending msg7

     producer sending msg8

     producer sending msg9

     producer sending msg10

     producer sending msg11

     producer sending msg12
     In Consumer received msg12

     producer sending msg13
     In Consumer received msg13

     producer sending msg14
     In Consumer received msg14

     producer sending msg15
     In Consumer received msg15

     producer sending msg16
     In Consumer received msg16

     producer sending msg17
     In Consumer received msg17

     producer sending msg18
     In Consumer received msg18

     producer sending msg19
     In Consumer received msg19

     producer sending msg20
     In Consumer received msg20

     producer sending msg21
     In Consumer received msg21

EDITED：添加生产者向消费者发送消息的监听器功能。我使用默认的生产者配置没有覆盖它

public synchronized void onValueChanged(final MonitorEvent event_) {


    // Get the value from the DBR
    try {
        final DBR dbr = event_.getDBR();

        final String[] val = (String[]) dbr.getValue();

        producer1.producer.send(new KeyedMessage<String, Signal>         
                    (KafkaProperties.topic,new Signal(messageNo)));
        System.out.println("producer sending msg"+messageNo);

        messageNo++;


    } catch (Exception ex) {
        ex.printStackTrace();
    }
}

Answer 1

尝试将props.put("request.required.acks", "1")添加到生产者配置中。默认情况下，生产者不会等待确认，并且无法保证消息传递。因此，如果您在测试之前启动代理，生产者可能会在代理完全初始化之前开始发送消息，并且可能会丢失前几条消息。
尝试将props.put("auto.offset.reset", "smallest")添加到使用者配置中。它等于kafka-console-consumer.sh的--from-beginning选项。如果您的消费者比生产者晚开始并且Zookeeper中没有保存偏移数据，那么默认情况下它将仅开始消费新消息（请参阅文档中的Consumer configs）。

Answer 2

这可能是由于没有分区而不是消费者。检查主题是否仅使用单个分区创建，然后您将不会错过消费者中的任何消息。

Apache Kafka中消费者消费消息的延迟

2 个答案: