code: public static StringConsumers buildConsumer(
              final String zookeeperConfig,//
              final String topic,//
              final String groupId, //
              final IMessageListener<String> listener) {
          return buildConsumer(zookeeperConfig, topic, groupId, listener, 2);
      }
docs: create a consumer
  
  @param zookeeperConfig connect config of zookeeper; ex: 127.0.0.1:2181/jafka
  @param topic           the topic to be watched
  @param groupId         grouping the consumer clients
  @param listener        message listener
  @return the real consumer