Getting nullpointer exception at w.toSeq.toDS()
in the below code.
var w = new ListBuffer[String]()
jList match {
case Some(x) => {
for (record <- x) {
w += mapper.writeValueAsString(record)
}
}
case None => println(s"No data read from file : ${f}")
}
import spark.implicits._
val jsonDataSet = w.toSeq.toDS()
Any idea what's wrong here?
It looks like it's not issue with toSeq.toDS()
. The piece code which you shared should work without any error/exception. I have prepared test data as below and able to run successfully. Please find sample code as below. It should be issue with some other piece of code. I would request you to share entire code.
import org.apache.spark.sql.SparkSession
import scala.collection.mutable.ListBuffer
object TestToSeqToDs extends App {
val spark = SparkSession
.builder()
.master("local")
.appName("Test toSeq.toDS() function")
.getOrCreate()
def jList(): Option[Seq[String]] = {
try {
Some(Seq(("john"), ("Edward")))
} catch {
case e: Exception => None
}
}
var w = new ListBuffer[String]()
jList match {
case Some(x) => {
for (record <- x) {
w += record
}
}
case None => println("That didn't work.")
}
import spark.implicits._
val jsonDataSet = w.toSeq.toDS()
//OR
val jsonDataSet = w.toDS()
println(jsonDataSet.show())
+------+
| value|
+------+
| john|
|Edward|
+------+
}
Thanks!
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.