scala – 如何在DataFrame中解开数组(来自JSON)？

val signalsJsonRdd = sqlContext.jsonRDD(signalsJson)

下面是架构. datapayload是一个项目数组.我想爆炸项目数组以获取数据框,其中每一行都是datapayload中的项目.我尝试基于this答案做一些事情,但似乎我需要在案例Row(arr：Array […])语句中对项目的整个结构进行建模.我可能错过了一些东西.

val payloadDfs = signalsJsonRdd.explode($"data.datapayload"){ 
    case org.apache.spark.sql.Row(arr: Array[String]) =>  arr.map(Tuple1(_)) 
}

上面的代码抛出了一个scala.MatchError,因为实际Row的类型与Row(arr：Array [String])非常不同.可能有一种简单的方法可以做我想要的,但我找不到它.请帮忙.

架构给出如下

signalsJsonRdd.printSchema()

root
 |-- _corrupt_record: string (nullable = true)
 |-- data: struct (nullable = true)
 |    |-- dataid: string (nullable = true)
 |    |-- datapayload: array (nullable = true)
 |    |    |-- element: struct (containsNull = true)
 |    |    |    |-- Reading: struct (nullable = true)
 |    |    |    |    |-- A2DPActive: boolean (nullable = true)
 |    |    |    |    |-- Accuracy: double (nullable = true)
 |    |    |    |    |-- Active: boolean (nullable = true)
 |    |    |    |    |-- Address: string (nullable = true)
 |    |    |    |    |-- Charging: boolean (nullable = true)
 |    |    |    |    |-- Connected: boolean (nullable = true)
 |    |    |    |    |-- DeviceName: string (nullable = true)
 |    |    |    |    |-- Guid: string (nullable = true)
 |    |    |    |    |-- HandsFree: boolean (nullable = true)
 |    |    |    |    |-- Header: double (nullable = true)
 |    |    |    |    |-- Heading: double (nullable = true)
 |    |    |    |    |-- Latitude: double (nullable = true)
 |    |    |    |    |-- Longitude: double (nullable = true)
 |    |    |    |    |-- PositionSource: long (nullable = true)
 |    |    |    |    |-- Present: boolean (nullable = true)
 |    |    |    |    |-- Radius: double (nullable = true)
 |    |    |    |    |-- SSID: string (nullable = true)
 |    |    |    |    |-- SSIDLength: long (nullable = true)
 |    |    |    |    |-- SpeedInKmh: double (nullable = true)
 |    |    |    |    |-- State: string (nullable = true)
 |    |    |    |    |-- Time: string (nullable = true)
 |    |    |    |    |-- Type: string (nullable = true)
 |    |    |    |-- Time: string (nullable = true)
 |    |    |    |-- Type: string (nullable = true)