scala - 使用 scala 转换 Spark 中的数据时，多个构造函数具有相同数量的参数异常

Question

下面是代码

    def findUniqueGroupInMetadata(sc: SparkContext): Unit = {
    val merchantGroup = sc.cassandraTable("local_pb",     "merchant_metadata").select("group_name")

try {
  val filterByWithGroup = merchantGroup.filter {
    row =>
      row.getStringOption("group_name") match {
        case Some(s: String) if (s != null) => true
        case None => false
      }
  }.map(row => row.getStringOption("group_name").get.capitalize)


  //filterByWithGroup.take(15).foreach(data => println("merchantGroup => " + data))
  filterByWithGroup.saveToCassandra("local_pb", "merchant_group", SomeColumns("group_name"))
} catch {
  case e: Exception => println(e.printStackTrace())

}

}

异常=>

java.lang.IllegalArgumentException: Multiple constructors with the same number of parameters not allowed.
    at com.datastax.spark.connector.util.Reflect$.methodSymbol(Reflect.scala:16)
    at com.datastax.spark.connector.util.ReflectionUtil$.constructorParams(ReflectionUtil.scala:63)
    at com.datastax.spark.connector.mapper.DefaultColumnMapper.<init>(DefaultColumnMapper.scala:45)
    at com.datastax.spark.connector.mapper.LowPriorityColumnMapper$class.defaultColumnMapper(ColumnMapper.scala:47)
    at com.datastax.spark.connector.mapper.ColumnMapper$.defaultColumnMapper(ColumnMapper.scala:51)

Answer 1

我在查看了一些博客后找到了答案。

当我将 RDD[String] 转换为 RDD[Tuple1[String]] 时，一切都很顺利。所以基本上为了将数据保存到 Cassandra，数据需要是 RDD[TupleX[String]] 类型，这里 x 可以是 1,2,3... 或数据可以是 RDD[SomeCaseClass]