Java FetchRequest類代碼示例

import kafka.api.FetchRequest; //導入依賴的package包/類
public static void main(String[] args) throws Exception {
	final String topic = "test2";
	String clientId = "LowLevelConsumerClient1";
	SimpleConsumer simpleConsumer = new SimpleConsumer(
			"192.168.1.186", 9092, 6000000, 64 * 1000000, clientId);
	FetchRequest req = new FetchRequestBuilder().clientId(clientId)
							.addFetch(topic, 0, 0L, 1000000)
							.addFetch(topic, 1, 0L, 1000000)
							.addFetch(topic, 2, 0L, 1000000)
							.build();
	FetchResponse rep = simpleConsumer.fetch(req);						
	ByteBufferMessageSet messageSet = rep.messageSet(topic, 0);
	for(MessageAndOffset messageAndOffset : messageSet) {
		ByteBuffer payload = messageAndOffset.message().payload();
		long offset = messageAndOffset.offset();
		byte[] bytes = new byte[payload.limit()];
		payload.get(bytes);
		System.out.println("Offset : " + offset + ", Payload : " + new String(bytes, "UTF-8"));
	}
}
 

import kafka.api.FetchRequest; //導入依賴的package包/類
public static void main(String[] args) throws Exception {
	final String topic = "topic1";
	String clientID = "DemoLowLevelConsumer1";
	SimpleConsumer simpleConsumer = new SimpleConsumer("kafka0", 9092, 100000, 64 * 1000000, clientID);
	FetchRequest req = new FetchRequestBuilder().clientId(clientID)
			.addFetch(topic, 0, 0L, 50).addFetch(topic, 1, 0L, 5000).addFetch(topic, 2, 0L, 1000000).build();
	FetchResponse fetchResponse = simpleConsumer.fetch(req);
	ByteBufferMessageSet messageSet = (ByteBufferMessageSet) fetchResponse.messageSet(topic, 0);
	for (MessageAndOffset messageAndOffset : messageSet) {
		ByteBuffer payload = messageAndOffset.message().payload();
		long offset = messageAndOffset.offset();
		byte[] bytes = new byte[payload.limit()];
		payload.get(bytes);
		System.out.println("Offset:" + offset + ", Payload:" + new String(bytes, "UTF-8"));
	}
}
 

import kafka.api.FetchRequest; //導入依賴的package包/類
private byte[] fetchLatestRecordPayloadBytes(SimpleConsumer kafkaConsumer) {
  FetchRequest fetchRequest = new FetchRequestBuilder().addFetch(destinationTopic, 0, 0, 1000000).build();
  FetchResponse response = kafkaConsumer.fetch(fetchRequest);

  Iterator<MessageAndOffset> messageSetItr = response.messageSet(destinationTopic, 0).iterator();

  // Fast forward to the message at the latest offset in the topic
  MessageAndOffset latestMessage = new MessageAndOffset(new Message(new byte[] { }), 0L);
  while (messageSetItr.hasNext()) {
    latestMessage = messageSetItr.next();
  }

  ByteBuffer payload = latestMessage.message().payload();
  byte[] bytes = new byte[payload.limit()];
  payload.get(bytes);
  return bytes;
}
 

import kafka.api.FetchRequest; //導入依賴的package包/類
private FetchRequest buildFetchRequest(long offset) {
  //1. maxWaitTime is the maximum amount of time in milliseconds to block waiting if insufficient data is
  //   available at the time the request is issued.

  //2. minFetchSize is the minimum number of bytes of messages that must be available to give a response. If the
  //   client sets this to 0 the server will always respond immediately, however if there is no new data since their
  //   last request they will just get back empty message sets. If this is set to 1, the server will respond as soon
  //   as at least one partition has at least 1 byte of data or the specified timeout occurs. By setting higher
  //   values in combination with the timeout the consumer can tune for throughput and trade a little additional
  //   latency for reading only large chunks of data (e.g. setting MaxWaitTime to 100 ms and setting MinBytes to 64k
  //   would allow the server to wait up to 100ms to try to accumulate 64k of data before responding).

  //3. maxFetchSize is the maximum bytes to include in the message set for this partition.
  //   This helps bound the size of the response.
  LOG.info("Building fetch request with clientId {}, minBytes {}, maxWait {}, topic {}, partition {}, offset {}, " +
    "max fetch size {}.", clientName, minFetchSize, maxWaitTime, topic, partition, offset, maxFetchSize);
  return new FetchRequestBuilder()
    .clientId(clientName)
    .minBytes(minFetchSize)
    .maxWait(maxWaitTime)
    .addFetch(topic, partition, offset, maxFetchSize)
    .build();
}
 

import kafka.api.FetchRequest; //導入依賴的package包/類
private ByteBufferMessageSet getMessageSetSince(long offset, int timeoutInMs)  {
    if (timeoutInMs < 0) {
        throw new IllegalArgumentException(String.format("Timeout must not lower than 0, timeout is: %d", timeoutInMs));
    }
    FetchRequest request = new FetchRequestBuilder()
            .clientId(generateClientId())
            .addFetch(assignedTopicPartition.topic(), assignedTopicPartition.partition(), offset, consumerConfig.bufferSize())
            .maxWait(timeoutInMs)
            .minBytes(consumerConfig.bufferSize())
            .build();
    FetchResponse response = partitionConsumer.fetch(request);
    if (response.hasError()) {
        short errorCode = response.errorCode(assignedTopicPartition.topic(), assignedTopicPartition.partition());
        // @todo retry during broker failover
        throw new PartitionConsumerException(ErrorMapping.exceptionFor(errorCode));
    }
    return response.messageSet(assignedTopicPartition.topic(), assignedTopicPartition.partition());
}
 

import kafka.api.FetchRequest; //導入依賴的package包/類
@Override
  public void run()
  {
    long offset = 0;
    while (isAlive) {
      // create a fetch request for topic “topic1”, partition 0, current offset, and fetch size of 1MB
      FetchRequest fetchRequest = new FetchRequestBuilder().clientId("default_client").addFetch("topic1", 1, offset, 1000000).build();

//      FetchRequest fetchRequest = new FetchRequest("topic1", 0, offset, 1000000);

      // get the message set from the consumer and print them out
      ByteBufferMessageSet messages = consumer.fetch(fetchRequest).messageSet("topic1", 1);
      Iterator<MessageAndOffset> itr = messages.iterator();

      while (itr.hasNext() && isAlive) {
        MessageAndOffset msg = itr.next();
        // advance the offset after consuming each message
        offset = msg.offset();
        logger.debug("consumed: {} offset: {}", byteBufferToString(msg.message().payload()).toString(), offset);
        receiveCount++;
      }
    }
  }
 

import kafka.api.FetchRequest; //導入依賴的package包/類
/** 返回消費的消息Map, 指定offset
 * <li>(Key為Topic name, Value為返回消息的消息List
 * 
 * @param topics The topic names
 * @param partitions Topic position
 * @param offsets	Starting byte offset
 * @return
 * @throws Exception
 */
static Map<String, List<String>> fetch(SimpleConsumer simpleConsumer, String[] topics, int[] partitions, long[] offsets) throws Exception{
	FetchRequest fetchRequest = getFetchRequest(simpleConsumer,topics, partitions, offsets);
	FetchResponse fetchResponse = simpleConsumer.fetch(fetchRequest);
	
	Map<String, List<String>> retMap = new HashMap<String, List<String>>();
	for (int i = 0; i < topics.length; i++) {
		String topic = topics[i];
		List list = new ArrayList<String>();
		retMap.put(topic, list);
		
		ByteBufferMessageSet messageSet = fetchResponse.messageSet(topic, partitions[i]);
		
		for (MessageAndOffset messageAndOffset : messageSet) {
			ByteBuffer payload = messageAndOffset.message().payload();
			byte[] bytes = new byte[payload.limit()];
			payload.get(bytes);
			String msg = new String(bytes, "UTF-8");
			list.add(msg);
		}
	}
	
	return retMap;
}
 

import kafka.api.FetchRequest; //導入依賴的package包/類
private void openFetchRequest()
{
    if (messageAndOffsetIterator == null) {
        log.debug("Fetching %d bytes from offset %d (%d - %d). %d messages read so far", KAFKA_READ_BUFFER_SIZE, cursorOffset, split.getStart(), split.getEnd(), totalMessages);
        FetchRequest req = new FetchRequestBuilder()
                .clientId("presto-worker-" + Thread.currentThread().getName())
                .addFetch(split.getTopicName(), split.getPartitionId(), cursorOffset, KAFKA_READ_BUFFER_SIZE)
                .build();

        // TODO - this should look at the actual node this is running on and prefer
        // that copy if running locally. - look into NodeInfo
        SimpleConsumer consumer = consumerManager.getConsumer(split.getNodes().get(0));

        FetchResponse fetchResponse = consumer.fetch(req);
        if (fetchResponse.hasError()) {
            short errorCode = fetchResponse.errorCode(split.getTopicName(), split.getPartitionId());
            log.warn("Fetch response has error: %d", errorCode);
            throw new PrestoException(KAFKA_SPLIT_ERROR, "could not fetch data from Kafka, error code is '" + errorCode + "'");
        }

        messageAndOffsetIterator = fetchResponse.messageSet(split.getTopicName(), split.getPartitionId()).iterator();
    }
}
 

import kafka.api.FetchRequest; //導入依賴的package包/類
public List<byte[]> readMessages(String topic) {
  SimpleConsumer consumer = new SimpleConsumer("localhost", 6667, 100000, 64 * 1024, "consumer");
  FetchRequest req = new FetchRequestBuilder()
          .clientId("consumer")
          .addFetch(topic, 0, 0, 100000)
          .build();
  FetchResponse fetchResponse = consumer.fetch(req);
  Iterator<MessageAndOffset> results = fetchResponse.messageSet(topic, 0).iterator();
  List<byte[]> messages = new ArrayList<>();
  while(results.hasNext()) {
    ByteBuffer payload = results.next().message().payload();
    byte[] bytes = new byte[payload.limit()];
    payload.get(bytes);
    messages.add(bytes);
  }
  consumer.close();
  return messages;
}
 

import kafka.api.FetchRequest; //導入依賴的package包/類
private void fetchMore()
{
    FetchRequest fetchRequest = this.builder
            .clientId(split.getClientId())
            .addFetch(split.getTopicName(), split.getPartitionId(),
                    nextFetchOffset, DEFAULT_BUFFER_SIZE).build();
    response = consumer.fetch(fetchRequest);
    this.currentResponseIter = null;
    if (response != null)
    {
        List<MessageAndOffset> currentResponseList = new ArrayList<MessageAndOffset>();
        for (MessageAndOffset messageAndOffset : response.messageSet(
                split.getTopicName(), split.getPartitionId()))
        {
            currentResponseList.add(messageAndOffset);
        }
        this.currentResponseIter = currentResponseList.size() > 0 ? currentResponseList.iterator() : null;
    }
}
 

import kafka.api.FetchRequest; //導入依賴的package包/類
/**
 * THIS METHOD HAS SIDE EFFECTS - it will update {@code currentMessageItr} (if necessary) and then return true iff
 * the iterator still has elements to be read. If you call {@link scala.collection.Iterator#next()} when this method
 * returns false, you risk a {@link NullPointerException} OR a no-more-elements exception.
 * 
 * @return true if you can call {@link scala.collection.Iterator#next()} on {@code currentMessageItr}.
 */
@VisibleForTesting
boolean continueItr() {
    final long remaining = end - currentOffset;
    if (!canCallNext() && remaining > 0) {
        final int theFetchSize = (fetchSize > remaining) ? (int) remaining : fetchSize;
        LOG.debug(String.format("%s fetching %d bytes starting at offset %d", split.toString(), theFetchSize,
                currentOffset));
        final FetchRequest request = new FetchRequest(split.getPartition().getTopic(), split.getPartition()
                .getPartId(), currentOffset, theFetchSize);
        final ByteBufferMessageSet msg = consumer.fetch(request);
        final int errorCode = msg.getErrorCode();
        if (errorCode == ErrorMapping.OffsetOutOfRangeCode()) {
            return false;
        }
        if (errorCode != ErrorMapping.NoError()) {
            ErrorMapping.maybeThrowException(errorCode);
        } // --> else we try to grab the next iterator
        currentMessageItr = msg.iterator();
        currentOffset += msg.validBytes();
    }
    return canCallNext();
}
 

import kafka.api.FetchRequest; //導入依賴的package包/類
@Override
public void doWork() {
    Utils.inLock(partitionMapLock, new Function0<Object>() {
        @Override
        public Object apply() {
            if (partitionMap.isEmpty())
                Utils.await(partitionMapCond, 200L, TimeUnit.MILLISECONDS);

            Utils.foreach(partitionMap, new Callable2<TopicAndPartition, Long>() {
                @Override
                public void apply(TopicAndPartition topicAndPartition, Long offset) {
                    fetchRequestBuilder.addFetch(topicAndPartition.topic, topicAndPartition.partition,
                            offset, fetchSize);
                }
            });
            return null;
        }
    });

    FetchRequest fetchRequest = fetchRequestBuilder.build();
    if (!fetchRequest.requestInfo.isEmpty())
        processFetchRequest(fetchRequest);
}
 

import kafka.api.FetchRequest; //導入依賴的package包/類
public boolean fetchMore () throws IOException {
    if (!hasMore()) return false;
    
    FetchRequest fetchRequest = 
        new FetchRequest(_request.getTopic(), _request.getPartition(), _offset, _bufferSize);
    List<FetchRequest> array = new ArrayList<FetchRequest>();
    array.add(fetchRequest);

    long tempTime = System.currentTimeMillis();
    _response = _consumer.multifetch(array);
    if(_response != null)
        _respIterator = _response.iterator();
    _requestTime += (System.currentTimeMillis() - tempTime);
    
    return true;
}
 

import kafka.api.FetchRequest; //導入依賴的package包/類
public static BatchMeta emitPartitionBatchNew(KafkaConfig config, int partition, SimpleConsumer consumer, TransactionAttempt attempt, BatchOutputCollector collector, BatchMeta lastMeta) {
    long offset = 0;
    if(lastMeta!=null) {
        offset = lastMeta.nextOffset;
    }
    ByteBufferMessageSet msgs;
    try {
       msgs = consumer.fetch(new FetchRequest(config.topic, partition % config.partitionsPerHost, offset, config.fetchSizeBytes));
    } catch(Exception e) {
        if(e instanceof ConnectException) {
            throw new FailedFetchException(e);
        } else {
            throw new RuntimeException(e);
        }
    }
    long endoffset = offset;
    for(MessageAndOffset msg: msgs) {
        emit(config, attempt, collector, msg.message());
        endoffset = msg.offset();
    }
    BatchMeta newMeta = new BatchMeta();
    newMeta.offset = offset;
    newMeta.nextOffset = endoffset;
    return newMeta;
}
 

import kafka.api.FetchRequest; //導入依賴的package包/類
public static void main(String[] args) {
		Properties props = new Properties();
//	props.put("zk.connect","10.15.62.76:2181");
//		props.put("groupid","testgroup");
		
		SimpleConsumer consumer = new SimpleConsumer("10.15.62.70",9092,10000,1024000);
		long offset =  0; 
		int count = 0;
		String str1 = "";
	//	while(true){
			FetchRequest fetchRequest  = new FetchRequest("topic1114",3,offset,10000000);//���һ��������һ���������ݵ������byte
			ByteBufferMessageSet messages = consumer.fetch(fetchRequest);
			for(MessageAndOffset msg  :messages){
				count++;
				ByteBuffer buffer = msg.message().payload();
				byte[] bytes = new byte[buffer.remaining()];
				buffer.get(bytes);
				String str = new String(bytes);
				System.out.println(str);
				offset = msg.offset();
				System.out.println("offset: " + offset);
			}
			System.out.println("------------ count= " + count);
	//	}
	}