kafka KafkaStream的iterator()方法不会执行？

 String consumeTopic = "Tflowmsg_1";
        Map<String, Integer> topicCountMap = new HashMap<String, Integer>();
        topicCountMap.put(consumeTopic, new Integer(1));
        Map<String, List<KafkaStream<byte[], byte[]>>> consumerMap = consumer.createMessageStreams(topicCountMap);
        KafkaStream<byte[], byte[]> kafkaStream = consumerMap.get(consumeTopic).get(0);
        ConsumerIterator<byte[], byte[]> it = kafkaStream.iterator();//此行代码不会执行，停在这里
        System.out.println("iterator:"+it);
        while (it.hasNext()) {
            System.out.println(new String(it.next().message()));
        }

最近在学kafka，上面这段代码执行到KafkaStream的iterator()方法时就停住了（好像阻塞了），不会继续往下执行，请教大神可能出错的情况？

http://www.oschina.net/question/2452605_2181259