我正在将一些Scala Spark UDAF从UserDefinedAggregateFunction迁移到Aggregator。其中一个将Array[String]作为输入，当我在本地测试中执行Aggregator时，我得到了一个奇怪的异常。我已经将代码减少到一个非常基本的Aggregator，但当我阅读Arrays时，我仍然得到这个错误。我对其他输入类型没有问题。
简单的例子如下：

class ArrayInputAggregator extends Aggregator[Array[String], Int, Int] with Serializable {

    override def zero = {0}

    override def reduce(buffer: Int, newItem: Array[String]): Int = {
      buffer + newItem.length
    }

    override def merge(b1: Int, b2: Int): Int = {
      b1 + b2
    }

    override def finish(reduction: Int): Int = reduction
    def bufferEncoder: Encoder[Int] = Encoders.scalaInt
    def outputEncoder: Encoder[Int] = Encoders.scalaInt
  }
}

字符串
我用这段代码测试它：

val test = udaf(new ArrayInputAggregator())

val d = spark
      .sql("select array('asd','tre','asd') arr")
      .groupBy()
      .agg(test($"arr").as("cnt"))

d.show

型
这是我得到的例外：
2023-12-24 12：06：24，678错误spark.executor.Executor -在阶段0.0中的任务0.0中出现异常（TID 0）java.lang.NullPointerException：null at org.apache.spark.sql. catalytic.expressions.objects.MapObjects$.apply（objects.scala：682）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql.catalyst.analysis.Analyzer$ResolveValidizer$$anonfun$apply$31$$anonfun$applyOrElse$172$anonfun$10.applyOrElse（Analyzer.scala：3033）~[spark-catalytic_2.12-3.0.0.jar：3.0.0]，位于org.apache.spark.sql.catalyst.analysis.Analyzer$ResolveValidizer$$anonfun$apply$31$$anonfun$applyOrElse$172$anonfun$10.applyOrElse（Analyzer.scala：3029）~[spark-catalyst_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql.catalyst.trees.TreeNode.$anonfun$transformDown$1（TreeNode.scala：309）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql. catalytic.trees.CurrentOrigin$.withOrigin（TreeNode.scala：72）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql. catalytic.trees.TreeNode.transformDown（TreeNode.scala：309）~[spark-catalyst_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql.catalyst.trees.TreeNode.$anonfun$transformDown$3（TreeNode.scala：314）~[spark-catalyst_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql.catalyst.trees.TreeNode.$anonfun$mapChildren$1（TreeNode.scala：399）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql. catalytic.treeNode.mapProductIterator（TreeNode.scala：237）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql. catalytic.trees.TreeNode.mapChildren（TreeNode.scala：397）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql. catalytic.trees.TreeNode.mapChildren（TreeNode.scala：350）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql. catalytic.trees.TreeNode.transformDown（TreeNode.scala：314）~[spark-catalytic_2.12-3.0.0.jar：3.0.0]，位于org.apache.spark.sql.catalyst.analysis.Analyzer$ResolveValidizer$$anonfun$apply$31$$anonfun$applyOrElse$172.applyOrElse（Analyzer.scala：3029）~[spark-catalytic_2.12-3.0.0.jar：3.0.0]，位于org.apache.spark.sql.catalyst.analysis.Analyzer$ResolveValidizer$$anonfun$apply$31$$anonfun$applyOrElse$172.applyOrElse（Analyzer.scala：3018）~[spark-catalyst_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql.catalyst.trees.TreeNode.$anonfun$transformDown$1（TreeNode.scala：309）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql. catalytic.trees.CurrentOrigin$.withOrigin（TreeNode.scala：72）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql. catalytic.trees.TreeNode.transformDown（TreeNode.scala：309）~[spark-catalytic_2.12-3.0.0.jar：3.0.0]在org.apache.spark.sql.catalyst.plans.QueryPlan.$anonfun$transformExpressionsDown$1（QueryPlan.scala：96）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql.catalyst.plans.QueryPlan.$anonfun$mapExpressions$1（QueryPlan.scala：118）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql. catalytic.trees.CurrentOrigin$.withOrigin（TreeNode.scala：72）~[spark-catalyst_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql.catalyst.plans.QueryPlan.transformExpression$1（QueryPlan.scala：118）~[spark-catalyst_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql.catalyst.plans.QueryPlan.recursiveTransform$1（QueryPlan.scala：129）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql.catalyst.plans.QueryPlan.$anonfun$mapExpressions$4（QueryPlan.scala：139）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql. catalytic.trees.TreeNode.mapProductIterator（TreeNode.scala：237）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql. catalytic.plans.QueryPlan.mapExpressions（QueryPlan.scala：139）~[spark-catalytic_2.12-3.0.0.jar：3.0.0] at org.apache.spark.sql. catalytic.plans.QueryPlan.transformExpressionsDown（QueryPlan.scala：96）
(it继续下去）