kafka消费者代码不运行完全

Question

我正在尝试一个简单的 kafka 生产者消费者客户端 api，我的生产者 class 工作正常，因为我可以从控制台看到消费者中的消息但是当我是运行消费者时代码什么都没有显示，我不知道是什么问题或我哪里做错了

这是生产者代码是 -

package com.app.test;
import java.util.Properties;
import kafka.javaapi.producer.Producer;
import kafka.producer.KeyedMessage;
import kafka.producer.ProducerConfig;

public class SimpleProducer {
    private static Producer<Integer, String> producer;
    private final Properties props = new Properties();public    SimpleProducer()
    {
      props.put("metadata.broker.list", "localhost:9092");
      props.put("serializer.class", "kafka.serializer.StringEncoder");
      props.put("request.required.acks", "1");
      producer = new Producer<Integer, String>(new ProducerConfig(props));
    }
public static void main(String[] args) {
    SimpleProducer sp = new SimpleProducer();
    String topic = "test4";
    String messageStr = "hello";
    KeyedMessage<Integer, String> data = new KeyedMessage<Integer, String>(topic, messageStr);
    System.out.println("producer : "+producer);
    producer.send(data);
    producer.close();
  }
}

消费者 class 是 -

package com.app.test;

import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;

import kafka.consumer.Consumer;
import kafka.consumer.ConsumerConfig;
import kafka.consumer.ConsumerIterator;
import kafka.consumer.KafkaStream;
import kafka.javaapi.consumer.ConsumerConnector;

public class SimpleHLConsumer {

  private final ConsumerConnector consumer;
  private final String topic;

  public SimpleHLConsumer(String zookeeper, String groupId, String topic) {
      Properties props = new Properties();
    props.put("zookeeper.connect", zookeeper);
    props.put("group.id", groupId);
    props.put("zookeeper.session.timeout.ms", "500");
    props.put("zookeeper.sync.time.ms", "250");
    props.put("auto.commit.interval.ms", "1000");

    consumer = Consumer.createJavaConsumerConnector(
    new ConsumerConfig(props));
    this.topic = topic;
  }



  public void testConsumer() {


    Map<String, Integer> topicCount = new HashMap<String, Integer>();
        // Define single thread for topic
    topicCount.put(topic, new Integer(1));      

    System.out.println("check1");

    Map<String, List<KafkaStream<byte[], byte[]>>> consumerStreams = consumer.createMessageStreams(topicCount);

    System.out.println("check2");
    List<KafkaStream<byte[], byte[]>> streams = consumerStreams.get(topic);

   for (KafkaStream stream : streams) {
        System.out.println("test----");
        System.out.println("test----"+stream.toString());
        ConsumerIterator<byte[], byte[]> consumerIte = stream.iterator();
        while (consumerIte.hasNext()) {
            try {
                System.out.println("Message from Single Topic: " + new String(consumerIte.next().message(), "UTF-8"));
            } catch (UnsupportedEncodingException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }
    if (consumer != null)
      consumer.shutdown();
  }



  public static void main(String[] args) {

    String topic = "test4";
SimpleHLConsumer simpleHLConsumer = new SimpleHLConsumer("localhost:2181", "testgroup", topic);
    simpleHLConsumer.testConsumer();
  }
}

为了检查，我在 testConsumer() 方法中使用 sysout 进行了 2 次检查，因此虽然运行仅显示 check1，即代码未到达 check2，我认为 [=13 存在一些问题=]，那是什么原因，我该如何解决呢？

Answer 1

代码没有问题。

只需构建包含 kafka-version（您正在使用的 kafka 版本）的 jar 和运行它并尝试从生产者控制台发送消息。

希望对您有所帮助。

kafka消费者代码不运行完全

kafka consumer code is not running completely

apache-kafka

kafka-consumer-api