Java Consumer類代碼示例

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
@Override
public void execute(ServiceContext ctx) throws Exception {
    active = true;
    receivedIds = new GridConcurrentHashSet<>();

    Properties config = new Properties();
    config.putAll(dataRecoveryConfig.getConsumerConfig());
    config.put(ConsumerConfig.GROUP_ID_CONFIG, ReceivedTransactionsListenerImpl.class.getSimpleName());
    config.put(ConsumerConfig.ENABLE_AUTO_COMMIT_CONFIG, true);
    try (Consumer<ByteBuffer, ByteBuffer> consumer = kafkaFactory.consumer(config)) {
        consumer.subscribe(Arrays.asList(dataRecoveryConfig.getRemoteTopic(), dataRecoveryConfig.getReconciliationTopic()));
        while (active) {
            ConsumerRecords<ByteBuffer, ByteBuffer> poll = consumer.poll(500);
            for (ConsumerRecord<ByteBuffer, ByteBuffer> record : poll) {
                TransactionMetadata metadata = serializer.deserialize(record.key());
                receivedIds.add(metadata.getTransactionId());
            }
            consumer.commitSync();
        }
    }
}
 

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
/**
 * Returns up to `maxMessages` by reading via the provided consumer (the topic(s) to read from
 * are already configured in the consumer).
 *
 * @param topic          Kafka topic to read messages from
 * @param consumer       Kafka consumer
 * @param waitTime       Maximum wait time in milliseconds
 * @param maxMessages    Maximum number of messages to read via the consumer
 * @return The KeyValue elements retrieved via the consumer
 */
private static <K, V> List<KeyValue<K, V>> readKeyValues(final String topic,
                                                         final Consumer<K, V> consumer, final long waitTime, final int maxMessages) {
  final List<KeyValue<K, V>> consumedValues;
  consumer.subscribe(Collections.singletonList(topic));
  final int pollIntervalMs = 100;
  consumedValues = new ArrayList<>();
  int totalPollTimeMs = 0;
  while (totalPollTimeMs < waitTime &&
          continueConsuming(consumedValues.size(), maxMessages)) {
    totalPollTimeMs += pollIntervalMs;
    final ConsumerRecords<K, V> records = consumer.poll(pollIntervalMs);
    for (final ConsumerRecord<K, V> record : records) {
      consumedValues.add(new KeyValue<>(record.key(), record.value()));
    }
  }
  return consumedValues;
}
 

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
/**
 * This test simulates executing many commands and each of them use their own InMemoryQueryRepository. We need
 * to re-create the repo outside of the command to ensure it has the most up to date values inside of it.
 *
 * @param ryaInstance - The rya instance the repository is connected to. (not null)
 * @param createTopic - Set this to true if the topic doesn't exist yet.
 */
private QueryRepository makeQueryRepository(final String ryaInstance, final boolean createTopic) {
    requireNonNull(ryaInstance);

    // Make sure the topic that the change log uses exists.
    final String changeLogTopic = KafkaTopics.queryChangeLogTopic("" + ryaInstance);
    if(createTopic) {
        kafka.createTopic(changeLogTopic);
    }

    // Setup the QueryRepository used by the test.
    final Producer<?, QueryChange> queryProducer = KafkaTestUtil.makeProducer(kafka, StringSerializer.class, QueryChangeSerializer.class);
    final Consumer<?, QueryChange>queryConsumer = KafkaTestUtil.fromStartConsumer(kafka, StringDeserializer.class, QueryChangeDeserializer.class);
    final QueryChangeLog changeLog = new KafkaQueryChangeLog(queryProducer, queryConsumer, changeLogTopic);
    return new InMemoryQueryRepository(changeLog);
}
 

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
@Override
@SuppressWarnings("unchecked")
public void afterPropertiesSet() throws Exception {
    if (topics == null && topicPatternString == null) {
        throw new IllegalArgumentException("topic info must not be null");
    }
    Assert.notEmpty(configs, "configs must not be null");
    Assert.notNull(payloadListener, "payloadListener must be null");
    String valueDeserializerKlass = (String) configs.get("value.deserializer");
    configs.put("value.deserializer", "org.apache.kafka.common.serialization.ByteArrayDeserializer");
    Consumer<String, byte[]> consumer = new KafkaConsumer<>(configs);

    Deserializer valueDeserializer = createDeserializer(valueDeserializerKlass);
    valueDeserializer.configure(configs, false);

    if (topics != null) {
        listenableConsumer =
                new ListenableTracingConsumer<>(consumer, Arrays.asList(topics), valueDeserializer);
    } else {
        listenableConsumer =
                new ListenableTracingConsumer<>(consumer, Pattern.compile(topicPatternString), valueDeserializer);
    }
    if (payloadListener != null) {
        listenableConsumer.addListener(payloadListener);
    }
    listenableConsumer.start();
}
 

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
private void loadRunningConf(String reloadMsgJson) {
    String notifyEvtName = reloadMsgJson == null ? "loaded" : "reloaded";
    try {
        //加載zk中的配置信息
        this.confMap = FullPullHelper.loadConfProps(zkConnect, topologyId, zkTopoRoot, Constants.ZkTopoConfForFullPull.FULL_PULL_SRC_TOPIC);
        this.MAX_FLOW_THRESHOLD = (Integer) confMap.get(FullPullHelper.RUNNING_CONF_KEY_MAX_FLOW_THRESHOLD);
        LOG.info("MAX_FLOW_THRESHOLD is {} on DataShardsSplittingSpout.loadRunningConf", MAX_FLOW_THRESHOLD);
        this.commonProps = (Properties) confMap.get(FullPullHelper.RUNNING_CONF_KEY_COMMON);
        this.dsName = commonProps.getProperty(Constants.ZkTopoConfForFullPull.DATASOURCE_NAME);
        this.fullPullSrcTopic = commonProps.getProperty(Constants.ZkTopoConfForFullPull.FULL_PULL_SRC_TOPIC);
        this.consumer = (Consumer<String, byte[]>) confMap.get(FullPullHelper.RUNNING_CONF_KEY_CONSUMER);
        this.zkService = (ZkService) confMap.get(FullPullHelper.RUNNING_CONF_KEY_ZK_SERVICE);

        LOG.info("Running Config is " + notifyEvtName + " successfully for DataShardsSplittingSpout!");
    } catch (Exception e) {
        LOG.error(notifyEvtName + "ing running configuration encountered Exception!", e);
    } finally {
        FullPullHelper.saveReloadStatus(reloadMsgJson, "splitting-spout", true, zkConnect);
    }
}
 

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
private void loadRunningConf(String reloadMsgJson) {
    try {
        this.confMap = FullPullHelper.loadConfProps(zkConnect, topologyId, zkTopoRoot, Constants.ZkTopoConfForFullPull.FULL_PULL_MEDIANT_TOPIC);
        this.MAX_FLOW_THRESHOLD = (Integer) confMap.get(FullPullHelper.RUNNING_CONF_KEY_MAX_FLOW_THRESHOLD);
        this.commonProps = (Properties) confMap.get(FullPullHelper.RUNNING_CONF_KEY_COMMON);
        this.dsName = commonProps.getProperty(Constants.ZkTopoConfForFullPull.DATASOURCE_NAME);
        this.zkService = (ZkService) confMap.get(FullPullHelper.RUNNING_CONF_KEY_ZK_SERVICE);
        this.consumer =  (Consumer<String, byte[]>)confMap.get(FullPullHelper.RUNNING_CONF_KEY_CONSUMER);

        String notifyEvtName = reloadMsgJson == null ? "loaded" : "reloaded";
        LOG.info("Running Config is " + notifyEvtName + " successfully for DataPullingSpout!");
    } catch (Exception e) {
        LOG.error("Loading running configuration encountered Exception!", e);
        throw e;
    } finally {
        FullPullHelper.saveReloadStatus(reloadMsgJson, "pulling-spout", true, zkConnect);
    }
}
 

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
/**
 * createConsumer - create a new consumer
 * @return
 * @throws Exception
 */
private Consumer<String, String> createConsumer() throws Exception {
    Properties props = ConfUtils.getProps(CONSUMER_PROPS);
    Consumer<String, String> consumer = new KafkaConsumer<>(props);
   
    // Seek to end automatically
    List<TopicPartition> pts = topics.stream().map(s -> new TopicPartition(s, 0)).collect(Collectors.toList());
    consumer.assign(pts);
    if(rollBack==0){
        consumer.seekToEnd(pts);  
    }else{
        for (TopicPartition topicPartition : pts) {
            consumer.seek(topicPartition, consumer.position(topicPartition)-rollBack);
            logger.info("Consumer seeked to -500000 :"+consumer.position(topicPartition));
        }    
    }  
    return consumer;
}
 

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
/**
 * createConsumer - create a new consumer
 * @return
 * @throws Exception
 */
private Consumer<String, String> createConsumer() throws Exception {

    // Seek to end automatically
    TopicPartition dataTopicPartition = new TopicPartition(topicName, 0);
    List<TopicPartition> topics = Arrays.asList(dataTopicPartition);

    Properties props = ConfUtils.getProps(CONSUMER_PROPS);
    Consumer<String, String> consumer = new KafkaConsumer<>(props);
    consumer.assign(topics);

    if(offset == -1){
        consumer.seekToEnd(topics);
        logger.info("Consumer seek to end");
    }else{
        consumer.seek(dataTopicPartition, offset);
        logger.info(String.format("read changed as offset: %s", consumer.position(dataTopicPartition)));
    }
    return consumer;
}
 

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
public void seekToTransaction(DataRecoveryConfig config, long transactionId, KafkaFactory kafkaFactory,
    String groupId) {
    String topic = config.getLocalTopic();
    Properties consumerProperties = PropertiesUtil.propertiesForGroup(config.getConsumerConfig(), groupId);

    try (Consumer<ByteBuffer, ByteBuffer> consumer = kafkaFactory.consumer(consumerProperties)) {
        List<PartitionInfo> partitionInfos = consumer.partitionsFor(topic);
        Map<TopicPartition, Long> seekMap = new HashMap<>(partitionInfos.size());

        for (PartitionInfo partitionInfo : partitionInfos) {
            seekMap.put(new TopicPartition(topic, partitionInfo.partition()), transactionId);
        }
        consumer.assign(seekMap.keySet());
        Map<TopicPartition, OffsetAndTimestamp> foundOffsets = consumer.offsetsForTimes(seekMap);
        Map<TopicPartition, OffsetAndMetadata> offsetsToCommit = new HashMap<>();

        for (Map.Entry<TopicPartition, OffsetAndTimestamp> entry : foundOffsets.entrySet()) {
            if (entry.getValue() != null) {
                offsetsToCommit.put(entry.getKey(), new OffsetAndMetadata(entry.getValue().offset()));
            }
        }
        consumer.commitSync(offsetsToCommit);
    }
}
 

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
private void pollCommunicateOnce(Consumer<ByteBuffer, ByteBuffer> consumer) {
    ConsumerRecords<ByteBuffer, ByteBuffer> records = consumer.poll(POLL_TIMEOUT);

    if (records.isEmpty()) {
        if (!stalled && checkStalled(consumer)) {
            LOGGER.info("[I] Loader stalled {} / {}", f(leadId), f(localLoaderId));
            stalled = true;
            lead.notifyLocalLoaderStalled(leadId, localLoaderId);
        }
        // ToDo: Consider sending empty messages for heartbeat sake.
        return;
    }
    if (stalled) {
        stalled = false;
    }
    MutableLongList committedIds = new LongArrayList(records.count());

    for (ConsumerRecord<ByteBuffer, ByteBuffer> record : records) {
        committedIds.add(record.timestamp());
    }
    committedIds.sortThis();
    lead.updateInitialContext(localLoaderId, committedIds);
    consumer.commitSync();
}
 

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
/**
 * Create {@link StandbyTask} with its assigned partitions
 *
 * @param id             the ID of this task
 * @param applicationId  the ID of the stream processing application
 * @param partitions     the collection of assigned {@link TopicPartition}
 * @param topology       the instance of {@link ProcessorTopology}
 * @param consumer       the instance of {@link Consumer}
 * @param config         the {@link StreamsConfig} specified by the user
 * @param metrics        the {@link StreamsMetrics} created by the thread
 * @param stateDirectory the {@link StateDirectory} created by the thread
 */
StandbyTask(final TaskId id,
            final String applicationId,
            final Collection<TopicPartition> partitions,
            final ProcessorTopology topology,
            final Consumer<byte[], byte[]> consumer,
            final ChangelogReader changelogReader,
            final StreamsConfig config,
            final StreamsMetrics metrics,
            final StateDirectory stateDirectory) {
    super(id, applicationId, partitions, topology, consumer, changelogReader, true, stateDirectory, null, config);

    // initialize the topology with its own context
    processorContext = new StandbyContextImpl(id, applicationId, config, stateMgr, metrics);

    log.debug("{} Initializing", logPrefix);
    initializeStateStores();
    processorContext.initialized();
    checkpointedOffsets = Collections.unmodifiableMap(stateMgr.checkpointed());
}
 

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
public GlobalStreamThread(final ProcessorTopology topology,
                          final StreamsConfig config,
                          final Consumer<byte[], byte[]> globalConsumer,
                          final StateDirectory stateDirectory,
                          final Metrics metrics,
                          final Time time,
                          final String threadClientId) {
    super(threadClientId);
    this.time = time;
    this.config = config;
    this.topology = topology;
    this.consumer = globalConsumer;
    this.stateDirectory = stateDirectory;
    long cacheSizeBytes = Math.max(0, config.getLong(StreamsConfig.CACHE_MAX_BYTES_BUFFERING_CONFIG) /
            (config.getInt(StreamsConfig.NUM_STREAM_THREADS_CONFIG) + 1));
    this.streamsMetrics = new StreamsMetricsImpl(metrics, threadClientId, Collections.singletonMap("client-id", threadClientId));
    this.cache = new ThreadCache(threadClientId, cacheSizeBytes, streamsMetrics);
}
 

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
/**
 * Wait until enough data (key-value records) has been consumed.
 *
 * @param consumerConfig     Kafka Consumer configuration
 * @param topic              Topic to consume from
 * @param expectedNumRecords Minimum number of expected records
 * @param waitTime           Upper bound in waiting time in milliseconds
 * @return All the records consumed, or null if no records are consumed
 * @throws InterruptedException
 * @throws AssertionError       if the given wait time elapses
 */
public static <K, V> List<KeyValue<K, V>> waitUntilMinKeyValueRecordsReceived(final Properties consumerConfig,
                                                                              final String topic,
                                                                              final int expectedNumRecords,
                                                                              final long waitTime) throws InterruptedException {
    final List<KeyValue<K, V>> accumData = new ArrayList<>();
    try (final Consumer<K, V> consumer = createConsumer(consumerConfig)) {
        final TestCondition valuesRead = new TestCondition() {
            @Override
            public boolean conditionMet() {
                final List<KeyValue<K, V>> readData =
                    readKeyValues(topic, consumer, waitTime, expectedNumRecords);
                accumData.addAll(readData);
                return accumData.size() >= expectedNumRecords;
            }
        };
        final String conditionDetails =
            "Expecting " + expectedNumRecords + " records from topic " + topic +
                " while only received " + accumData.size() + ": " + accumData;
        TestUtils.waitForCondition(valuesRead, waitTime, conditionDetails);
    }
    return accumData;
}
 

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
/**
 * Wait until enough data (value records) has been consumed.
 *
 * @param consumerConfig     Kafka Consumer configuration
 * @param topic              Topic to consume from
 * @param expectedNumRecords Minimum number of expected records
 * @param waitTime           Upper bound in waiting time in milliseconds
 * @return All the records consumed, or null if no records are consumed
 * @throws InterruptedException
 * @throws AssertionError       if the given wait time elapses
 */
public static <V> List<V> waitUntilMinValuesRecordsReceived(final Properties consumerConfig,
                                                            final String topic,
                                                            final int expectedNumRecords,
                                                            final long waitTime) throws InterruptedException {
    final List<V> accumData = new ArrayList<>();
    try (final Consumer<Object, V> consumer = createConsumer(consumerConfig)) {
        final TestCondition valuesRead = new TestCondition() {
            @Override
            public boolean conditionMet() {
                final List<V> readData =
                    readValues(topic, consumer, waitTime, expectedNumRecords);
                accumData.addAll(readData);
                return accumData.size() >= expectedNumRecords;
            }
        };
        final String conditionDetails =
            "Expecting " + expectedNumRecords + " records from topic " + topic +
                " while only received " + accumData.size() + ": " + accumData;
        TestUtils.waitForCondition(valuesRead, waitTime, conditionDetails);
    }
    return accumData;
}
 

import org.apache.kafka.clients.consumer.Consumer; //導入依賴的package包/類
/**
 * Returns up to `maxMessages` by reading via the provided consumer (the topic(s) to read from
 * are already configured in the consumer).
 *
 * @param topic          Kafka topic to read messages from
 * @param consumer       Kafka consumer
 * @param waitTime       Maximum wait time in milliseconds
 * @param maxMessages    Maximum number of messages to read via the consumer
 * @return The KeyValue elements retrieved via the consumer
 */
private static <K, V> List<KeyValue<K, V>> readKeyValues(final String topic,
    final Consumer<K, V> consumer, final long waitTime, final int maxMessages) {
    final List<KeyValue<K, V>> consumedValues;
    consumer.subscribe(Collections.singletonList(topic));
    final int pollIntervalMs = 100;
    consumedValues = new ArrayList<>();
    int totalPollTimeMs = 0;
    while (totalPollTimeMs < waitTime &&
        continueConsuming(consumedValues.size(), maxMessages)) {
        totalPollTimeMs += pollIntervalMs;
        final ConsumerRecords<K, V> records = consumer.poll(pollIntervalMs);
        for (final ConsumerRecord<K, V> record : records) {
            consumedValues.add(new KeyValue<>(record.key(), record.value()));
        }
    }
    return consumedValues;
}