java.lang.ClassCastException:无法将java.lang.String强制转换为scala.collection.Seq [英] java.lang.ClassCastException: java.lang.String cannot be cast to scala.collection.Seq

问题描述

我正在做这样的事情

val domainList = data1.select("columnname","domainvalues").where(col("domainvalues").isNotNull).map(r =>  (r.getString(0), r.getList[String](1).asScala.toList)).collect()

domainList的类型应为Array [(String，List [String])]

domainList should be of Type Array[(String, List[String])]

对于输入DF:

+-------------+----------------------------------------+
|columnname   |domainvalues                            |
+-------------+----------------------------------------+
|predchurnrisk|Very High,High,Medium,Low               |
|userstatus   |Active,Lapsed,Renew                     |
|predinmarket |Very High,High,Medium,Low               |
|predsegmentid|High flyers,Watching Pennies,Big pockets|
|usergender   |Male,Female,Others                      |
+-------------+----------------------------------------+

我遇到的错误是

java.lang.ClassCastException: java.lang.String cannot be cast to scala.collection.Seq
    at org.apache.spark.sql.Row$class.getSeq(Row.scala:283)
    at org.apache.spark.sql.catalyst.expressions.GenericRow.getSeq(rows.scala:166)
    at org.apache.spark.sql.Row$class.getList(Row.scala:291)
    at org.apache.spark.sql.catalyst.expressions.GenericRow.getList(rows.scala:166)
    at com.fis.sdi.ade.batch.SFTP.Test$$anonfun$6.apply(Test.scala:53)
    at com.fis.sdi.ade.batch.SFTP.Test$$anonfun$6.apply(Test.scala:53)
    at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIteratorForCodegenStage2.mapelements_doConsume_0$(Unknown Source)
    at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIteratorForCodegenStage2.deserializetoobject_doConsume_0$(Unknown Source)

我应该如何解决?

推荐答案

看起来您的第二列包含String值，您可以使用 df.printSchema()进行检查.在这种情况下，您可以尝试使用 .split(，")

looks like that your second column contains String values, you can check it by using df.printSchema(). In this case you can try getting this list using .split(",")

.map(r =>  (r.getString(0), r.getString(1).split(",")).collect()

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