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.KafkaConsumer;
7 import org.apache.kafka.common.serialization.StringDeserializer;
9 import java.time.Duration;
10 import java.util.Arrays;
11 import java.util.Properties;
15 public class SimpleConsumer
17 private final String id;
18 private final String topic;
19 private final KafkaConsumer<String, String> consumer;
21 private long consumed = 0;
22 private volatile boolean running = true;
23 private volatile boolean done = false;
25 public SimpleConsumer(String broker, String topic, String groupId, String clientId)
27 Properties props = new Properties();
28 props.put("bootstrap.servers", broker);
29 props.put("group.id", groupId); // ID für die Offset-Commits
30 props.put("client.id", clientId); // Nur zur Wiedererkennung
31 props.put("key.deserializer", StringDeserializer.class.getName());
32 props.put("value.deserializer", StringDeserializer.class.getName());
34 consumer = new KafkaConsumer<>(props);
45 log.info("{} - Subscribing to topic test", id);
46 consumer.subscribe(Arrays.asList("test"));
51 ConsumerRecords<String, String> records =
52 consumer.poll(Duration.ofSeconds(1));
54 // Do something with the data...
56 log.info("{} - Received {} messages", id, records.count());
57 for (ConsumerRecord<String, String> record : records)
61 "{} - {}: {}/{} - {}={}",
76 log.error("{} - Unexpected error: {}", id, e.toString());
80 log.info("{} - Closing the KafkaConsumer", id);
82 log.info("{}: Consumed {} messages in total, exiting!", id, consumed);
88 public static void main(String[] args) throws Exception
90 String broker = ":9092";
91 String topic = "test";
92 String groupId = "my-group";
93 String clientId = "DEV";
108 SimpleConsumer instance = new SimpleConsumer(broker, topic, groupId, clientId);
110 Runtime.getRuntime().addShutdownHook(new Thread(() ->
112 instance.running = false;
113 while (!instance.done)
115 log.info("Waiting for main-thread...");
120 catch (InterruptedException e) {}
122 log.info("Shutdown completed.");
126 "Running SimpleConsumer: broker={}, topic={}, group-id={}, client-id={}",