在 UDF 函数 Spark Scala 中使用方法

Question

我想在用户设计的函数中使用位于另一个类中的方法，但它不起作用。

我有一个方法：

 def traitementDataFrameEleve(sc:SparkSession, dfRedis:DataFrame, domainMail:String, dir:String):Boolean ={
     def loginUDF = udf((sn: String, givenName:String) => {
            LoginClass.GenerateloginPersone(sn,givenName,dfr)
          })

    dfEleve.withColumn("ENTPersonLogin",loginUDF(dfEleve("sn"),dfEleve("givenName")))
}

LoginClass 是一个包含 GenerateloginPerson 方法的类。

输出错误：

org.apache.spark.SparkException: Failed to execute user defined function(anonfun$loginUDF$1$1: (string, string) => string)
    at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIterator.processNext(Unknown Source)
    at org.apache.spark.sql.execution.BufferedRowIterator.hasNext(BufferedRowIterator.java:43)
    at org.apache.spark.sql.execution.WholeStageCodegenExec$$anonfun$8$$anon$1.hasNext(WholeStageCodegenExec.scala:377)
    at org.apache.spark.sql.execution.SparkPlan$$anonfun$2.apply(SparkPlan.scala:231)
    at org.apache.spark.sql.execution.SparkPlan$$anonfun$2.apply(SparkPlan.scala:225)
    at org.apache.spark.rdd.RDD$$anonfun$mapPartitionsInternal$1$$anonfun$apply$25.apply(RDD.scala:826)
    at org.apache.spark.rdd.RDD$$anonfun$mapPartitionsInternal$1$$anonfun$apply$25.apply(RDD.scala:826)
    at org.apache.spark.rdd.MapPartitionsRDD.compute(MapPartitionsRDD.scala:38)
    at org.apache.spark.rdd.RDD.computeOrReadCheckpoint(RDD.scala:323)
    at org.apache.spark.rdd.RDD.iterator(RDD.scala:287)
    at org.apache.spark.scheduler.ResultTask.runTask(ResultTask.scala:87)
    at org.apache.spark.scheduler.Task.run(Task.scala:99)
    at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:282)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.NullPointerException
    at org.apache.spark.sql.Dataset.schema(Dataset.scala:410)
    at org.apache.spark.sql.Dataset.printSchema(Dataset.scala:419)
    at IntegrationDonneesENTLea_V1_AcBordeaux.LoginClass$.GenerateloginPersone(LoginClass.scala:16)
    at IntegrationDonneesENTLea_V1_AcBordeaux.Eleve$$anonfun$loginUDF$1$1.apply(Eleve.scala:25)
    at IntegrationDonneesENTLea_V1_AcBordeaux.Eleve$$anonfun$loginUDF$1$1.apply(Eleve.scala:23)
    ... 16 more

谢谢。

Answer 1

不允许访问：

• 分布式数据结构（如Dataset 或RDD）。
• SparkConext / SparkSession

来自 Spark 任务（转换，udf 应用程序）。这就是你获得 NPE 的原因。