26.4. 线程例子

 

package cn.netkiller.ipo.test;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

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.errors.WakeupException;
import org.apache.kafka.common.serialization.StringDeserializer;

public class KafkaConsumerThread implements Runnable {
private final KafkaConsumer<String, String> consumer;
private final List<String> topics;

public KafkaConsumerThread(String groupId, List<String> topics) {
this.topics = topics;
Properties props = new Properties();
props.put("bootstrap.servers", "kafka.netkiller.cn:9092");
props.put("group.id", groupId);
props.put("key.deserializer", StringDeserializer.class.getName());
props.put("value.deserializer", StringDeserializer.class.getName());
this.consumer = new KafkaConsumer<String, String>(props);
}

public void run() {
try {
consumer.subscribe(this.topics);

while (true) {
ConsumerRecords<String, String> records = consumer.poll(Long.MAX_VALUE);
for (ConsumerRecord<String, String> record : records) {
Map<String, Object> data = new HashMap<>();
data.put("partition", record.partition());
data.put("offset", record.offset());
data.put("value", record.value());
System.out.println(data);
}
}
} catch (WakeupException e) {
// ignore for shutdown
} finally {
consumer.close();
}
}

public void shutdown() {
consumer.wakeup();
}

public static void main(String[] args) {
int numConsumers = 3;
String groupId = "consumer-tutorial-group";
List<String> topics = Arrays.asList("test");
ExecutorService executor = Executors.newFixedThreadPool(numConsumers);

final List<KafkaConsumerThread> consumers = new ArrayList<>();
for (int i = 0; i < numConsumers; i++) {
KafkaConsumerThread consumer = new KafkaConsumerThread(groupId, topics);
consumers.add(consumer);
executor.submit(consumer);
}

Runtime.getRuntime().addShutdownHook(new Thread() {
@Override
public void run() {
for (KafkaConsumerThread consumer : consumers) {
consumer.shutdown();
}
executor.shutdown();
try {
executor.awaitTermination(5000, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
});
}
}
  
 

原文出处：Netkiller 系列 手札
本文作者：陈景峯
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