import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;

import kafka.consumer.ConsumerConfig;
import kafka.consumer.ConsumerIterator;
import kafka.consumer.KafkaStream;
import kafka.javaapi.consumer.ConsumerConnector;
import kafka.serializer.StringDecoder;
import kafka.utils.VerifiableProperties;

public class KafkaConsumer {

private final ConsumerConnector consumer;

private KafkaConsumer() {
Properties props = new Properties();

// zookeeper 配置
props.put("zookeeper.connect", "192.168.170.185:2181");

// 消费者所在组
props.put("group.id", "testgroup");

// zk连接超时
props.put("zookeeper.session.timeout.ms", "4000");
props.put("zookeeper.sync.time.ms", "200");
props.put("auto.commit.interval.ms", "1000");
props.put("auto.offset.reset", "smallest");

// 序列化类
props.put("serializer.class", "kafka.serializer.StringEncoder");

ConsumerConfig config = new ConsumerConfig(props);

consumer = kafka.consumer.Consumer.createJavaConsumerConnector(config);
}

void consume() {
Map<String, Integer> topicCountMap = new HashMap<String, Integer>();
topicCountMap.put(KafkaProducer.TOPIC, new Integer(1));

StringDecoder keyDecoder = new StringDecoder(new VerifiableProperties());
StringDecoder valueDecoder = new StringDecoder(new VerifiableProperties());

Map<String, List<KafkaStream<String, String>>> consumerMap =
consumer.createMessageStreams(topicCountMap,keyDecoder,valueDecoder);
KafkaStream<String, String> stream = consumerMap.get(KafkaProducer.TOPIC).get(0);
ConsumerIterator<String, String> it = stream.iterator();

int messageCount = 0;
while (it.hasNext()){
System.out.println(it.next().message());
messageCount++;
if(messageCount == 100){
System.out.println("Consumer端一共消费了" + messageCount + "条消息！");
}
}
}

public static void main(String[] args) {
new KafkaConsumer().consume();
}
}

kafka java api消费者