求大佬指点：spark streaming无法对接kafka；
1. 程序中spark streaming可以消费子系统(ubuntu)上netcat发送的数据，
1. kafka自己的消费者可以消费自己生产的数据，
1. windows10上程序代码如下：
val kafkaParam = Map(
"bootstrap.servers" -> "localhost:9092",
"key.deserializer" -> classOf[StringDeserializer],
"value.deserializer" -> classOf[StringDeserializer],
"group.id" -> "recommender",
"auto.offset.reset" -> "latest"
)
// 创建一个DStream
val kafkaStream = KafkaUtils.createDirectStream[String, String](ssc,
LocationStrategies.PreferConsistent,
ConsumerStrategies.Subscribe[String, String](Array(config("kafka.topic")), kafkaParam)
)
控制台warn：
Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
overriding enable.auto.commit to false for executor
overriding auto.offset.reset to none for executor
overriding executor group.id to spark-executor-recommender
overriding receive.buffer.bytes to 65536 see KAFKA-3135
然后ssc.start()一直无反应，debug跟进，
发现卡在StreamingContext.scala里的 ThreadUtils.runInNewThread("streaming-start")这里，
再跟进 ThreadUtils.scala 里面
thread.setDaemon(isDaemon)
thread.start()
thread.join()
发现最终卡在这里：thread.join()，无报错信息
注：程序启动前已经在子系统（ubuntu）上已经启动了kafka
