Spark Map Job異常：對象不可序列化

Question

Ws類

package MPD1
    import java.util.UUID.randomUUID;
class Ws (typ:String,c:Float,t:Float,r:Float,a:Float,s:Float,cu:Float) {
  var styp=typ;
  var uid=randomUUID().toString;
  var cost :Float =c;
  var time :Float  =t;
  var reliability :Float =r;
  var availability :Float =a;
  var security: Float =s
  var customAttributes :Float=cu;
  def Ws(typ:String,c:Float,t:Float,r:Float,a:Float,s:Float){
    this.styp=typ;
    this.uid=randomUUID().toString;
    this.cost =c;
    this.time =t;
    this.reliability =r;
    this.availability =a;
    this.security=s;
    this.customAttributes=Float.MaxValue;
  }

  def display()={
    println("STyp : "+styp+"| UID : "+uid+"|"+"cost :"+cost+"|"+"time :"+time+"|"+"reliability :"+reliability+"|"+"availability :"+availability+"|"+"security :"+security+"|"+"customAttributes :"+customAttributes+"|");
  }

}

我要創建Ws類的對象然后對其進行Parallallize的主要功能，以便可以完成進一步的地圖精簡工作

package MPD1

import org.apache.spark.{SparkConf, SparkContext}
import scala.collection.mutable.ListBuffer
import java.lang.Exception
object test {
  def main(args: Array[String]) {
    try {
      val conf = new SparkConf().setAppName("Simple Application")
      val sc = new SparkContext(conf)

      println(" \nHello World from Scala!\n")
      var wsArray = new Array[MPD1.Ws](10000)
      var i: Int = 0;
      val filename = "/home/nazi/Downloads/file.csv";

      var lines = sc.textFile(filename)

      var rddWsAll=lines.map(f=>Functions.createdDS(f));
      rddWsAll.collect().take(10).foreach(f=>f.display())

      for (line <- lines) {
        var tempStr = line.split(",");
        println(tempStr(0).toString())
        var wsTemp: Ws = new Ws(tempStr(0).toString(), tempStr(2).toFloat, tempStr(3).toFloat, tempStr(4).toFloat, tempStr(5).toFloat, tempStr(6).toFloat, tempStr(7).toFloat);

        wsArray(i) = wsTemp;
        wsTemp.display();
        i = i + 1;
      }

    }
    catch {
      case e: javax.script.ScriptException => e.printStackTrace
    }

  }

}


package MPD1

object Functions {
 def createdDS(f:String):Ws={
   var tempStr = f.split(",");
   var wsTemp: Ws = new Ws(tempStr(0).toString(), tempStr(2).toFloat, tempStr(3).toFloat, tempStr(4).toFloat, tempStr(5).toFloat, tempStr(6).toFloat, tempStr(7).toFloat);

   return wsTemp

 }

}

我收到一個錯誤：

Exception in thread "main" org.apache.spark.SparkException: Job aborted due to stage failure: Task 0.0 in stage 0.0 (TID 0) had a not serializable result: MPD1.Ws
Serialization stack:
    - object not serializable (class: MPD1.Ws, value: MPD1.Ws@47acf13d)
    - element of array (index: 0)
    - array (class [LMPD1.Ws;, size 10000)
    ....

.....

我在地圖函數var rddWsAll=lines.map(f=>Functions.createdDS(f));使用Ws類var rddWsAll=lines.map(f=>Functions.createdDS(f)); 造成問題。 但是為什么不允許我們使用類創建rdds或只允許使用字符串創建rdds

我正在使用scalaVersion := "2.11.8" spark version :="2.2.1"

Answer 1

看起來類Ws不可序列化。 使Serializable為

class Ws extends java.io.Serializable (...

請注意，RDD默認情況下是可序列化的。