1 package de.juplo.kafka;
3 import lombok.extern.slf4j.Slf4j;
4 import org.apache.kafka.clients.consumer.ConsumerRecord;
5 import org.apache.kafka.clients.consumer.ConsumerRecords;
6 import org.apache.kafka.clients.consumer.Consumer;
7 import org.apache.kafka.clients.consumer.KafkaConsumer;
8 import org.apache.kafka.common.errors.WakeupException;
9 import org.apache.kafka.common.serialization.StringDeserializer;
11 import java.time.Duration;
12 import java.util.Arrays;
13 import java.util.Properties;
14 import java.util.concurrent.locks.Condition;
15 import java.util.concurrent.locks.Lock;
16 import java.util.concurrent.locks.ReentrantLock;
20 public class SimpleConsumer
22 private long consumed = 0;
23 private Consumer<String, String> consumer;
24 private Lock lock = new ReentrantLock();
25 private Condition stopped = lock.newCondition();
28 public SimpleConsumer()
30 this.consumer = null; // TODO: Eine Instanz von KafkaConsumer erzeugen
40 log.info("{} - Subscribing to topic test", id);
41 consumer.subscribe(Arrays.asList("test"));
46 // Über consumer.poll() Nachrichten abrufen und diese
47 // über log.info() ausgeben.
50 catch(WakeupException e)
52 log.info("{} - Closing the KafkaConsumer", id);
57 log.error("{} - Unexpected error: {}", id, e.toString());
61 log.info("{} - Shutting down...");
65 log.info("{} - DONE!");
71 log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
77 public static void main(String[] args) throws Exception
79 SimpleConsumer instance = new SimpleConsumer();
81 Runtime.getRuntime().addShutdownHook(new Thread(() ->
86 instance.consumer.wakeup();
87 instance.stopped.await();
89 catch (InterruptedException e)
91 log.warn("Interrrupted while waiting for the consumer to stop!", e);
95 instance.lock.unlock();