共计 3461 个字符，预计需要花费 9 分钟才能阅读完成。
序
本文主要展示一下如何使用 reactor-kafka
maven
<dependency>
<groupId>io.projectreactor.kafka</groupId>
<artifactId>reactor-kafka</artifactId>
<version>1.0.1.RELEASE</version>
</dependency>
准备
启动 zookeeper
cd zookeeper-3.4.13
sh bin/zkServer.sh start
ZooKeeper JMX enabled by default
ZooKeeper remote JMX Port set to 8999
ZooKeeper remote JMX authenticate set to false
ZooKeeper remote JMX ssl set to false
ZooKeeper remote JMX log4j set to true
Using config: zookeeper-3.4.13/bin/../conf/zoo.cfg
-n Starting zookeeper …
STARTED
启动 kafka
cd kafka_2.11-1.1.1
sh bin/kafka-server-start.sh config/server.properties
创建 topic
cd kafka_2.11-1.1.1
sh bin/kafka-topics.sh –create –topic demotopic –replication-factor 1 –partitions 3 –zookeeper localhost:2181
Created topic “demotopic”.
实例
producer
@Test
public void testProducer() throws InterruptedException {
Map<String, Object> props = new HashMap<>();
props.put(ProducerConfig.BOOTSTRAP_SERVERS_CONFIG, BOOTSTRAP_SERVERS);
props.put(ProducerConfig.CLIENT_ID_CONFIG, “sample-producer”);
props.put(ProducerConfig.ACKS_CONFIG, “all”);
props.put(ProducerConfig.KEY_SERIALIZER_CLASS_CONFIG, IntegerSerializer.class);
props.put(ProducerConfig.VALUE_SERIALIZER_CLASS_CONFIG, StringSerializer.class);
SenderOptions<Integer, String> senderOptions = SenderOptions.create(props);
KafkaSender<Integer, String> sender = KafkaSender.create(senderOptions);
SimpleDateFormat dateFormat = new SimpleDateFormat(“HH:mm:ss:SSS z dd MMM yyyy”);
CountDownLatch latch = new CountDownLatch(100);
sender.<Integer>send(Flux.range(1, 100)
.map(i -> SenderRecord.create(new ProducerRecord<>(TOPIC, i, “Message_” + i), i)))
.doOnError(e -> log.error(“Send failed”, e))
.subscribe(r -> {
RecordMetadata metadata = r.recordMetadata();
System.out.printf(“Message %d sent successfully, topic-partition=%s-%d offset=%d timestamp=%s\n”,
r.correlationMetadata(),
metadata.topic(),
metadata.partition(),
metadata.offset(),
dateFormat.format(new Date(metadata.timestamp())));
latch.countDown();
});
latch.await(10, TimeUnit.SECONDS);
sender.close();
}
consumer
@Test
public void testConsumer() throws InterruptedException {
Map<String, Object> props = new HashMap<>();
props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, BOOTSTRAP_SERVERS);
props.put(ConsumerConfig.CLIENT_ID_CONFIG, “sample-consumer”);
props.put(ConsumerConfig.GROUP_ID_CONFIG, “sample-group”);
props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, IntegerDeserializer.class);
props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
props.put(ConsumerConfig.AUTO_OFFSET_RESET_CONFIG, “earliest”);
ReceiverOptions<Integer, String> receiverOptions = ReceiverOptions.create(props);
SimpleDateFormat dateFormat = new SimpleDateFormat(“HH:mm:ss:SSS z dd MMM yyyy”);
CountDownLatch latch = new CountDownLatch(100);
ReceiverOptions<Integer, String> options = receiverOptions.subscription(Collections.singleton(TOPIC))
.addAssignListener(partitions -> log.debug(“onPartitionsAssigned {}”, partitions))
.addRevokeListener(partitions -> log.debug(“onPartitionsRevoked {}”, partitions));
Flux<ReceiverRecord<Integer, String>> kafkaFlux = KafkaReceiver.create(options).receive();
Disposable disposable = kafkaFlux.subscribe(record -> {
ReceiverOffset offset = record.receiverOffset();
System.out.printf(“Received message: topic-partition=%s offset=%d timestamp=%s key=%d value=%s\n”,
offset.topicPartition(),
offset.offset(),
dateFormat.format(new Date(record.timestamp())),
record.key(),
record.value());
offset.acknowledge();
latch.countDown();
});
latch.await(10, TimeUnit.SECONDS);
disposable.dispose();
}
小结
reactor-kafka 对 kafka 的 api 进行封装，改造为 reactive streams 模式，这样用起来更为顺手，熟悉 reactor 的开发人员可以轻车熟路。
doc
reactor-kafka-samples
Reactor Kafka Reference Guide
