| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.iotdb.kafka; |
| |
| import kafka.consumer.ConsumerConfig; |
| import kafka.consumer.KafkaStream; |
| import kafka.javaapi.consumer.ConsumerConnector; |
| import kafka.serializer.StringDecoder; |
| import kafka.utils.VerifiableProperties; |
| |
| 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; |
| |
| /** |
| * The class is to show how to get data from kafka through multi-threads. The data is sent by class |
| * KafkaProducer. |
| */ |
| public class KafkaConsumer { |
| |
| private ConsumerConnector consumer; |
| |
| private KafkaConsumer() { |
| /** Consumer configuration */ |
| Properties props = new Properties(); |
| |
| /** Zookeeper configuration */ |
| props.put("zookeeper.connect", "127.0.0.1:2181"); |
| props.put("group.id", "consumeGroup"); |
| props.put("zookeeper.session.timeout.ms", "400"); |
| props.put("zookeeper.sync.time.ms", "200"); |
| props.put("rebalance.max.retries", "5"); |
| props.put("rebalance.backoff.ms", "1200"); |
| props.put("auto.commit.interval.ms", "1000"); |
| |
| /** |
| * What to do when there is no initial offset in ZooKeeper or if an offset is out of range |
| * smallest : automatically reset the offset to the smallest offset |
| */ |
| props.put("auto.offset.reset", "smallest"); |
| |
| /** serializer class */ |
| props.put("serializer.class", "kafka.serializer.StringEncoder"); |
| |
| ConsumerConfig config = new ConsumerConfig(props); |
| consumer = kafka.consumer.Consumer.createJavaConsumerConnector(config); |
| } |
| |
| public static void main(String[] args) { |
| new KafkaConsumer().consume(); |
| } |
| |
| private void consume() { |
| /** Specify the number of consumer thread */ |
| Map<String, Integer> topicCountMap = new HashMap<>(); |
| topicCountMap.put(Constant.TOPIC, Constant.CONSUMER_THREAD_NUM); |
| |
| /** Specify data decoder */ |
| StringDecoder keyDecoder = new StringDecoder(new VerifiableProperties()); |
| StringDecoder valueDecoder = new StringDecoder(new VerifiableProperties()); |
| |
| Map<String, List<KafkaStream<String, String>>> consumerMap = |
| consumer.createMessageStreams(topicCountMap, keyDecoder, valueDecoder); |
| |
| List<KafkaStream<String, String>> streams = consumerMap.get(Constant.TOPIC); |
| ExecutorService executor = Executors.newFixedThreadPool(Constant.CONSUMER_THREAD_NUM); |
| for (final KafkaStream<String, String> stream : streams) { |
| executor.submit(new KafkaConsumerThread(stream)); |
| } |
| } |
| } |