使用Scala、Spark UDF中的类型多态性将一系列Map展平为Map

import org.apache.spark.sql.functions._
import org.apache.spark.sql.types._

val data = Seq(
  Map("name" -> "John", "age" -> 30),
  Map("name" -> "Alice", "age" -> 25),
  Map("name" -> "Bob", "age" -> 35)
)
val df = spark.createDataFrame(Seq(data)).toDF("maps")

val flattenMaps = udf((maps: Seq[Map[String, Any]]) => {
  maps.flatten.toMap
})

val flattenedDF = df.withColumn("flattenedMap", flattenMaps($"maps"))

flattenedDF.show(false)

+------------------------------------+------------------------+
|maps                                |flattenedMap            |
+------------------------------------+------------------------+
|[name -> John, age -> 30]            |[name -> John, age -> 30]|
|[name -> Alice, age -> 25]           |[name -> Alice, age -> 25]|
|[name -> Bob, age -> 35]             |[name -> Bob, age -> 35]  |
+------------------------------------+------------------------+