[Solved]-How to set the type of array with dataset in spark scala-scala

One option

case class Nested(D: Long, E: String)
case class TestClass (A: Long, B:String, C: Seq[Nested])

Usage:

spark.read.json(sc.parallelize(
  Seq("""{"A": 123, "B": "Hello world", "C": [{"D": 123, "E": "Spark"}]}"""
))).as[TestClass].show

+---+-----------+-------------+
|  A|          B|            C|
+---+-----------+-------------+
|123|Hello world|[[123,Spark]]|
+---+-----------+-------------+