执行时报错：
org.apache.spark.sql.AnalysisException: Unable to generate an encoder for inner class `cn.itcast.spark.sql.Intro$Person` without access to the scope that this class was defined in.
Try moving this class out of its parent class.;
解决方法：将case class Person(name:String,age:Int)这个样例类移动到父类的外面，就是移到最外面，不要让其包含任何的类中。