Kafka学习笔记-Java简单操作
Maven依赖包:
- <dependency>
- <groupId>org.apache.kafka</groupId>
- <artifactId>kafka-clients</artifactId>
- <version>0.8.2.1</version>
- </dependency>
- <dependency>
- <groupId>org.apache.kafka</groupId>
- <artifactId>kafka_2.11</artifactId>
- <version>0.8.2.1</version>
- </dependency>
代码如下:
- import java.util.Properties;
- import org.apache.kafka.clients.producer.Callback;
- import org.apache.kafka.clients.producer.KafkaProducer;
- import org.apache.kafka.clients.producer.ProducerRecord;
- import org.apache.kafka.clients.producer.RecordMetadata;
- import org.slf4j.Logger;
- import org.slf4j.LoggerFactory;
- public class KafkaProducerTest {
- private static final Logger LOG = LoggerFactory.getLogger(KafkaProducerTest.class);
- private static Properties properties = null;
- static {
- properties = new Properties();
- properties.put("bootstrap.servers", "centos.master:9092,centos.slave1:9092,centos.slave2:9092");
- properties.put("producer.type", "sync");
- properties.put("request.required.acks", "1");
- properties.put("serializer.class", "kafka.serializer.DefaultEncoder");
- properties.put("partitioner.class", "kafka.producer.DefaultPartitioner");
- properties.put("key.serializer", "org.apache.kafka.common.serialization.ByteArraySerializer");
- // properties.put("key.serializer", "org.apache.kafka.common.serialization.StringSerializer");
- properties.put("value.serializer", "org.apache.kafka.common.serialization.ByteArraySerializer");
- // properties.put("value.serializer", "org.apache.kafka.common.serialization.StringSerializer");
- }
- public void produce() {
- KafkaProducer<byte[], byte[]> kafkaProducer = new KafkaProducer<byte[],byte[]>(properties);
- ProducerRecord<byte[],byte[]> kafkaRecord = new ProducerRecord<byte[],byte[]>(
- "test", "kkk".getBytes(), "vvv".getBytes());
- kafkaProducer.send(kafkaRecord, new Callback() {
- public void onCompletion(RecordMetadata metadata, Exception e) {
- if(null != e) {
- LOG.info("the offset of the send record is {}", metadata.offset());
- LOG.error(e.getMessage(), e);
- }
- LOG.info("complete!");
- }
- });
- kafkaProducer.close();
- }
- public static void main(String[] args) {
- KafkaProducerTest kafkaProducerTest = new KafkaProducerTest();
- for (int i = 0; i < 10; i++) {
- kafkaProducerTest.produce();
- }
- }
- }
- import java.util.List;
- import java.util.Map;
- import java.util.Properties;
- import org.apache.kafka.clients.consumer.ConsumerConfig;
- import org.apache.kafka.clients.consumer.ConsumerRecord;
- import org.apache.kafka.clients.consumer.ConsumerRecords;
- import org.apache.kafka.clients.consumer.KafkaConsumer;
- import org.slf4j.Logger;
- import org.slf4j.LoggerFactory;
- public class KafkaConsumerTest {
- private static final Logger LOG = LoggerFactory.getLogger(KafkaConsumerTest.class);
- public static void main(String[] args) {
- Properties properties = new Properties();
- properties.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG,
- "centos.master:9092,centos.slave1:9092,centos.slave2:9092");
- properties.put(ConsumerConfig.GROUP_ID_CONFIG, "test-consumer-group");
- properties.put(ConsumerConfig.SESSION_TIMEOUT_MS, "1000");
- properties.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, "true");
- properties.put(ConsumerConfig.PARTITION_ASSIGNMENT_STRATEGY, "range");
- // properties.put(ConsumerConfig.PARTITION_ASSIGNMENT_STRATEGY, "roundrobin");
- properties.put(ConsumerConfig.AUTO_COMMIT_INTERVAL_MS_CONFIG, "10000");
- properties.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG,
- "org.apache.kafka.common.serialization.ByteArrayDeserializer");
- properties.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG,
- "org.apache.kafka.common.serialization.ByteArrayDeserializer");
- KafkaConsumer<byte[], byte[]> kafkaConsumer = new KafkaConsumer<byte[], byte[]>(properties);
- kafkaConsumer.subscribe("test");
- // kafkaConsumer.subscribe("*");
- boolean isRunning = true;
- while(isRunning) {
- Map<String, ConsumerRecords<byte[], byte[]>> results = kafkaConsumer.poll(100);
- if (null != results) {
- for (Map.Entry<String, ConsumerRecords<byte[], byte[]>> entry : results.entrySet()) {
- LOG.info("topic {}", entry.getKey());
- ConsumerRecords<byte[], byte[]> consumerRecords = entry.getValue();
- List<ConsumerRecord<byte[], byte[]>> records = consumerRecords.records();
- for (int i = 0, len = records.size(); i < len; i++) {
- ConsumerRecord<byte[], byte[]> consumerRecord = records.get(i);
- LOG.info("topic {} partition {}", consumerRecord.topic(), consumerRecord.partition());
- try {
- LOG.info("offset {} value {}", consumerRecord.offset(), new String(consumerRecord.value()));
- } catch (Exception e) {
- LOG.error(e.getMessage(), e);
- }
- }
- }
- }
- }
- kafkaConsumer.close();
- }
- }
发现KafkaConsumer的poll方法未实现
- @Override
- public Map<String, ConsumerRecords<K,V>> poll(long timeout) {
- // TODO Auto-generated method stub
- return null;
- }
后改为kafka.javaapi.consumer.SimpleConsumer实现,正常运行
- import java.nio.ByteBuffer;
- import java.util.ArrayList;
- import java.util.Collections;
- import java.util.HashMap;
- import java.util.List;
- import java.util.Map;
- import kafka.api.FetchRequest;
- import kafka.api.FetchRequestBuilder;
- import kafka.api.PartitionOffsetRequestInfo;
- import kafka.cluster.Broker;
- import kafka.common.ErrorMapping;
- import kafka.common.TopicAndPartition;
- import kafka.javaapi.FetchResponse;
- import kafka.javaapi.OffsetRequest;
- import kafka.javaapi.OffsetResponse;
- import kafka.javaapi.PartitionMetadata;
- import kafka.javaapi.TopicMetadata;
- import kafka.javaapi.TopicMetadataRequest;
- import kafka.javaapi.TopicMetadataResponse;
- import kafka.javaapi.consumer.SimpleConsumer;
- import kafka.message.MessageAndOffset;
- public class KafkaSimpleConsumerTest {
- private List<String> borkerList = new ArrayList<String>();
- public KafkaSimpleConsumerTest() {
- borkerList = new ArrayList<String>();
- }
- public static void main(String args[]) {
- KafkaSimpleConsumerTest kafkaSimpleConsumer = new KafkaSimpleConsumerTest();
- // 最大读取消息数量
- long maxReadNum = Long.parseLong("3");
- // 订阅的topic
- String topic = "test";
- // 查找的分区
- int partition = Integer.parseInt("0");
- // broker节点
- List<String> seeds = new ArrayList<String>();
- seeds.add("centos.master");
- seeds.add("centos.slave1");
- seeds.add("centos.slave2");
- // 端口
- int port = Integer.parseInt("9092");
- try {
- kafkaSimpleConsumer.run(maxReadNum, topic, partition, seeds, port);
- } catch (Exception e) {
- System.out.println("Oops:" + e);
- e.printStackTrace();
- }
- }
- public void run(long maxReadNum, String topic, int partition, List<String> seedBrokers, int port) throws Exception {
- // 获取指定topic partition的元数据
- PartitionMetadata metadata = findLeader(seedBrokers, port, topic, partition);
- if (metadata == null) {
- System.out.println("can't find metadata for topic and partition. exit");
- return;
- }
- if (metadata.leader() == null) {
- System.out.println("can't find leader for topic and partition. exit");
- return;
- }
- String leadBroker = metadata.leader().host();
- String clientName = "client_" + topic + "_" + partition;
- SimpleConsumer consumer = new SimpleConsumer(leadBroker, port, 100000, 64 * 1024, clientName);
- long readOffset = getLastOffset(consumer, topic, partition, kafka.api.OffsetRequest.EarliestTime(), clientName);
- int numErrors = 0;
- while (maxReadNum > 0) {
- if (consumer == null) {
- consumer = new SimpleConsumer(leadBroker, port, 100000, 64 * 1024, clientName);
- }
- FetchRequest req = new FetchRequestBuilder().clientId(clientName).addFetch(topic, partition, readOffset, 100000).build();
- FetchResponse fetchResponse = consumer.fetch(req);
- if (fetchResponse.hasError()) {
- numErrors++;
- short code = fetchResponse.errorCode(topic, partition);
- System.out.println("error fetching data from the broker:" + leadBroker + " reason: " + code);
- if (numErrors > 5)
- break;
- if (code == ErrorMapping.OffsetOutOfRangeCode()) {
- readOffset = getLastOffset(consumer, topic, partition, kafka.api.OffsetRequest.LatestTime(), clientName);
- continue;
- }
- consumer.close();
- consumer = null;
- leadBroker = findNewLeader(leadBroker, topic, partition, port);
- continue;
- }
- numErrors = 0;
- long numRead = 0;
- for (MessageAndOffset messageAndOffset : fetchResponse.messageSet(topic, partition)) {
- long currentOffset = messageAndOffset.offset();
- if (currentOffset < readOffset) {
- System.out.println("found an old offset: " + currentOffset + " expecting: " + readOffset);
- continue;
- }
- readOffset = messageAndOffset.nextOffset();
- ByteBuffer payload = messageAndOffset.message().payload();
- byte[] bytes = new byte[payload.limit()];
- payload.get(bytes);
- System.out.println(String.valueOf(messageAndOffset.offset()) + ": " + new String(bytes, "UTF-8"));
- numRead++;
- maxReadNum--;
- }
- if (numRead == 0) {
- try {
- Thread.sleep(1000);
- } catch (InterruptedException ie) {
- }
- }
- }
- if (consumer != null)
- consumer.close();
- }
- /**
- * 从活跃的Broker列表中找出指定Topic、Partition中的Leader Broker
- * @param seedBrokers
- * @param port
- * @param topic
- * @param partition
- * @return
- */
- private PartitionMetadata findLeader(List<String> seedBrokers, int port, String topic, int partition) {
- PartitionMetadata partitionMetadata = null;
- loop: for (String seedBroker : seedBrokers) {
- SimpleConsumer consumer = null;
- try {
- consumer = new SimpleConsumer(seedBroker, port, 100000, 64 * 1024, "leaderLookup");
- List<String> topics = Collections.singletonList(topic);
- TopicMetadataRequest topicMetadataRequest = new TopicMetadataRequest(topics);
- TopicMetadataResponse topicMetadataResponse = consumer.send(topicMetadataRequest);
- List<TopicMetadata> topicMetadatas = topicMetadataResponse.topicsMetadata();
- for (TopicMetadata topicMetadata : topicMetadatas) {
- for (PartitionMetadata pMetadata : topicMetadata.partitionsMetadata()) {
- if (pMetadata.partitionId() == partition) {
- partitionMetadata = pMetadata;
- break loop;
- }
- }
- }
- } catch (Exception e) {
- System.out.println("error communicating with broker [" + seedBroker + "] to find leader for [" + topic + ", " + partition + "] reason: " + e);
- } finally {
- if (consumer != null)
- consumer.close();
- }
- }
- if (partitionMetadata != null) {
- borkerList.clear();
- for (Broker replica : partitionMetadata.replicas()) {
- borkerList.add(replica.host());
- }
- }
- return partitionMetadata;
- }
- public static long getLastOffset(SimpleConsumer consumer, String topic, int partition, long whichTime, String clientName) {
- TopicAndPartition topicAndPartition = new TopicAndPartition(topic, partition);
- Map<TopicAndPartition, PartitionOffsetRequestInfo> requestInfo = new HashMap<TopicAndPartition, PartitionOffsetRequestInfo>();
- requestInfo.put(topicAndPartition, new PartitionOffsetRequestInfo(whichTime, 1));
- OffsetRequest request = new OffsetRequest(requestInfo, kafka.api.OffsetRequest.CurrentVersion(), clientName);
- OffsetResponse response = consumer.getOffsetsBefore(request);
- if (response.hasError()) {
- System.out.println("error fetching data offset data the broker. reason: " + response.errorCode(topic, partition));
- return 0;
- }
- long[] offsets = response.offsets(topic, partition);
- return offsets[0];
- }
- private String findNewLeader(String oldLeader, String topic, int partition, int port) throws Exception {
- for (int i = 0; i < 3; i++) {
- boolean goToSleep = false;
- PartitionMetadata metadata = findLeader(borkerList, port, topic, partition);
- if (metadata == null) {
- goToSleep = true;
- } else if (metadata.leader() == null) {
- goToSleep = true;
- } else if (oldLeader.equalsIgnoreCase(metadata.leader().host()) && i == 0) {
- goToSleep = true;
- } else {
- return metadata.leader().host();
- }
- if (goToSleep) {
- try {
- Thread.sleep(1000);
- } catch (InterruptedException ie) {
- }
- }
- }
- System.out.println("unable to find new leader after broker failure. exit");
- throw new Exception("unable to find new leader after broker failure. exit");
- }
- }
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