an Array[String] which consists all the Lists we want to listen to
the receiver' storage tragedy of received data, default as MEMORY_AND_DISK_2
a stream of (listname, value)
an Array[String] which consists all the Lists we want to listen to
the receiver' storage tragedy of received data, default as MEMORY_AND_DISK_2
a stream of (value)
a spark StreamingContext
RedisStreamingContext extends StreamingContext's functionality with Redis