Spark 讀取json字符串轉為DataFrame

來源：https://stackoverflow.com/questions/39619782/how-to-read-in-memory-json-string-into-spark-dataframe

---

先將字符串轉為RDD，再由RDD轉為DF。

From Spark SQL guide:

val otherPeopleRDD = spark.sparkContext.makeRDD(
"""{"name":"Yin","address":{"city":"Columbus","state":"Ohio"}}""" :: Nil)
val otherPeople = spark.read.json(otherPeopleRDD)
otherPeople.show()

This creates a DataFrame from an intermediate RDD (created by passing a String).