Scala - 存储在数据集中的类型缺少编码器

Question

我正在尝试在Scala 2.2中运行以下命令

   val x_test0 = cn_train.map( { case row => row.toSeq.toArray } )

我一直遇到以下错误

 error: Unable to find encoder for type stored in a Dataset.  Primitive types (Int, String, etc) and Product types (case classes) are supported by importing spark.implicits._  Support for serializing other types will be added in future releases.

我已经通过以下命令导入了implicits._：

val spark = SparkSession.builder.getOrCreate()
import spark.implicits._

Answer 1

该错误消息告诉您，它无法找到异类Encoder的{​​{1}}以将其保存在Array中。但是你可以得到Dataset RDD这样的内容：

Array