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Code Issues Actions 2 Packages Projects Releases Wiki Activity

KAFKA-14752: Improving the existing consumer examples (#13353) 

Reviewers: Guozhang Wang <wangguoz@gmail.com>
This commit is contained in:
Philip Nee 2023-03-07 16:24:38 -08:00 committed by GitHub
parent 6fbe4d85a2
commit b19ae7857b
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2 changed files with 26 additions and 5 deletions
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29
examples/src/main/java/kafka/examples/Consumer.java
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@ -17,17 +17,26 @@
package kafka.examples;
import org.apache.kafka.clients.consumer.ConsumerConfig;
import org.apache.kafka.clients.consumer.ConsumerRebalanceListener;
import org.apache.kafka.clients.consumer.ConsumerRecord;
import org.apache.kafka.clients.consumer.ConsumerRecords;
import org.apache.kafka.clients.consumer.KafkaConsumer;
import org.apache.kafka.common.TopicPartition;
import org.apache.kafka.common.errors.WakeupException;
import java.time.Duration;
import java.util.Collection;
import java.util.Collections;
import java.util.Optional;
import java.util.Properties;
import java.util.concurrent.CountDownLatch;
public class Consumer extends Thread {
/**
* A simple consumer thread that demonstrate subscribe and poll use case. The thread subscribes to a topic,
* then runs a loop to poll new messages, and print the message out. The thread closes until the target {@code
* numMessageToConsume} is hit or catching an exception.
*/
public class Consumer extends Thread implements ConsumerRebalanceListener {
private final KafkaConsumer<Integer, String> consumer;
private final String topic;
private final String groupId;
@ -48,8 +57,6 @@ public class Consumer extends Thread {
props.put(ConsumerConfig.GROUP_ID_CONFIG, groupId);
instanceId.ifPresent(id -> props.put(ConsumerConfig.GROUP_INSTANCE_ID_CONFIG, id));
props.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, "true");
props.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG, "1000");
props.put(ConsumerConfig.SESSION_TIMEOUT_MS_CONFIG, "30000");
props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.IntegerDeserializer");
props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, "org.apache.kafka.common.serialization.StringDeserializer");
if (readCommitted) {
@ -71,10 +78,14 @@ public class Consumer extends Thread {
@Override
public void run() {
try {
System.out.println("Subscribe to:" + this.topic);
consumer.subscribe(Collections.singletonList(this.topic), this);
do {
doWork();
} while (messageRemaining > 0);
System.out.println(groupId + " finished reading " + numMessageToConsume + " messages");
} catch (WakeupException e) {
// swallow the wakeup
} catch (Exception e) {
System.out.println("Unexpected termination, exception thrown:" + e);
} finally {
@ -82,7 +93,6 @@ public class Consumer extends Thread {
}
}
public void doWork() {
consumer.subscribe(Collections.singletonList(this.topic));
ConsumerRecords<Integer, String> records = consumer.poll(Duration.ofSeconds(1));
for (ConsumerRecord<Integer, String> record : records) {
System.out.println(groupId + " received message : from partition " + record.partition() + ", (" + record.key() + ", " + record.value() + ") at offset " + record.offset());
@ -91,6 +101,17 @@ public class Consumer extends Thread {
}
public void shutdown() {
this.consumer.close();
latch.countDown();
}
@Override
public void onPartitionsRevoked(Collection<TopicPartition> partitions) {
System.out.println("Revoking partitions:" + partitions);
}
@Override
public void onPartitionsAssigned(Collection<TopicPartition> partitions) {
System.out.println("Assigning partitions:" + partitions);
}
}

2
examples/src/main/java/kafka/examples/Producer.java
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@ -18,9 +18,9 @@ package kafka.examples;
import org.apache.kafka.clients.producer.Callback;
import org.apache.kafka.clients.producer.KafkaProducer;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.clients.producer.ProducerRecord;
import org.apache.kafka.clients.producer.RecordMetadata;
import org.apache.kafka.clients.producer.ProducerConfig;
import org.apache.kafka.common.serialization.IntegerSerializer;
import org.apache.kafka.common.serialization.StringSerializer;