在 Cassandra 表中写入时出现 UnsupportedOperationException

Question

我有以下课程：

case class AucLog(timestamp:  UUID, modelname: String, good: Int,
              list: List[Double])

class AucDatabase(override val connector : CassandraConnection)
extends Database[AucDatabase](connector) {
object users extends CMetrics with Connector
}
object AucDatabase extends AucDatabase(AucConnector.connector)

abstract class AucMetrics extends Table[AucMetrics, AucLog] {
 object id extends UUIDColumn with PartitionKey
 object name extends StringColumn
 object ud extends IntColumn
 object zob extends ListColumn[Double]
}

abstract class CMetrics extends AucMetrics with RootConnector {  
def store(metric : AucLog): Future[ResultSet] = {
insert.value(_.id, metric.timestamp)
  .value(_.name, metric.modelname)
  .value(_.ud, metric.good)
  .value(_.zob, metric.list)
  .consistencyLevel_=(ConsistencyLevel.ONE)
  .future()

}

DmpDatabase.create()
AucDatabase.create()

val pd = DmpDatabase.users.myselect()

val timeout = new Timeout(500000)
val result = Await.result(pd, timeout.duration)

"<--- this attempt to read from my database is working - no problemo   ---> "
val todf = result.records.map { elem => elem.idcat }
val rdd = spark.sparkContext.parallelize(todf)

import spark.implicits._
rdd.toDF().show(100)

---> I'm storing one line in my database to be sure that it is not empty when 
   i'm reading it. 
AucDatabase.users.store(new AucLog(UUIDs.timeBased(), "tyron", 0, List(0.1)))
val second = AucDatabase.users.myselect()
val resultmetric = Await.result(second, timeout.duration)

 -----> this line cause the Execption
val r = spark.sparkContext.parallelize(resultmetric.records).toDF().show(

我不明白的是，我对两个数据库做的事情基本上是一样的。然而，一个是抛出以下错误： UnsupportedOperationException : No encoder found for com.outworkers.phantom.dsl.UUID.

谢谢。

Answer 1

首先store 方法是宏生成的，所以你不需要创建一个。您遇到的问题可能根本与幻象无关，而是与某种 Spark 构造有关。

幻象UUID 只不过是java.util.UUID 的类型别名，所以我很惊讶没有默认类型的直接编码器。如果你帮我知道 Encoder 类的全名，包括包，我可以明确地弄清楚什么是坏的。