即使在 conf 中注册课程后，Kryo 序列化也没有注册

Question

I made a class Person and registered it but on runtime, it shows class not registered.Why is it showing so?

Exception in thread "main" org.apache.spark.SparkException: Job aborted due to stage failure: Failed to serialize task 0, not attempting to retry it. Exception during serialization: java.io.IOException: java.lang.IllegalArgumentException: Class is not registered: KyroExample$Person[]
Note: To register this class use: kryo.register(KyroExample$Person[].class);

Here is the sample code:

 val conf = new SparkConf().setAppName("kyroExample").setMaster("local")

  conf.set("spark.serializer","org.apache.spark.serializer.KryoSerializer")
  conf.registerKryoClasses(Array(classOf[Person],classOf[String])) //registered the class
  conf.set("spark.kryo.registrationRequired", "true")

  val sparkContext = new SparkContext(conf)

  case class Person(name:String, age:Int) //this is the class

  val personList: immutable.Seq[Person] = (1 to 100000).map(value=> Person(value+"",value))

  val rdd: RDD[Person] = sparkContext.parallelize(personList)

  val evenAge: RDD[Person] = rdd.filter(_.age %2 ==0)

  evenAge.persist(StorageLevel.MEMORY_ONLY_SER)
  evenAge.count()

  evenAge.persist(StorageLevel.MEMORY_ONLY_SER)
  evenAge.count()


  Thread.sleep(200000)

Answer 1

It worked after registering both use cases:

.registerKryoClasses(
      Array(classOf[Person],classOf[Array[Person]])
    )