创建RDD的三种方式

1、val rdd = sc.textFile...

val lines :RDD[String] = sc.textFile("./data/words")

2、val rdd = sc.parallelize(Seq[xx](... ...))

val result :RDD[String]= sc.parallelize(Array[String]("a","b","c"))

3、val rdd = sc.makeRDD(Seq[xx](... ...))

val result: RDD[(String, Int)] = sc.makeRDD(Array[(String, Int)](
      ("a", 10),
      ("b", 20),
      ("c", 30)
    ))
或
val result: RDD[Int] = sc.makeRDD(Array[Int](1,2,3,4,5,6))