Rdd无法调用toDF缘由

建立rdd方法1//use case class Person
  case class Person(name:String,age:Int)
  def rddToDFCase(sparkSession : SparkSession):DataFrame = {
    //导入隐饰操做，不然RDD没法调用toDF方法
    import sparkSession.implicits._
    val peopleRDD = sparkSession.sparkContext
      .textFile("file:/E:/scala_workspace/z_spark_study/people.txt",2)
      .map( x => x.split(",")).map( x => Person(x(0),x(1).trim().toInt)).toDF()
    peopleRDD

}

建立rdd方法2：

def rddToDF(sparkSession : SparkSession):DataFrame = {
    //设置schema结构
    val schema = StructType(
      Seq(
        StructField("name",StringType,true)          
        ,StructField("age",IntegerType,true)
      )
    )
    val rowRDD = sparkSession.sparkContext
      .textFile("file:/E:/scala_workspace/z_spark_study/people.txt",2)
      .map( x => x.split(",")).map( x => Row(x(0),x(1).trim().toInt))  
    sparkSession.createDataFrame(rowRDD,schema)
  }