Spark Streaming：广播变量，java.lang.ClassCastException-Java 学习之路

我尝试从存储在HDFS中的静态文本文件中读取数据，将其内容存储到ArrayBuffer中，而ArrayBuffer又应通过sparkContext.broadcast作为BroadcastVariable进行广播 . 我正在使用cloudera的spark，spark版本1.6.0-cdh5.7.0和spark-streaming_2.10 .

我使用spark-submit启动纱线上的应用程序：

spark-submit --class my.package.BroadcastStreamTest1 --master yarn --deploy-mode client --conf spark.executor.userClassPathFirst=true current.jar

当我这样做时，我得到一个java.lang.ClassCastException：无法将scala.Some的实例分配给org.apache.spark.Accumulator实例中的scala.Option类型的字段org.apache.spark.Accumulable.name相同的代码与硬编码ArrayBuffer一起使用工作完美，所以我认为它与静态文件资源有关...有谁知道我可能做错了什么？任何帮助赞赏 .

这不起作用：

object BroadcastStreamTest1 {

        def main(args: Array[String]) {
            val sparkConf = new SparkConf()
            val streamingContext = new StreamingContext(sparkConf, batchDuration = Seconds(10))

            val content = streamingContext.sparkContext
                .textFile("hdfs:///data/someTextFile.txt")
                .collect()
                .toBuffer[String]

            val broadCastVar = streamingContext.sparkContext.broadcast(content)
            broadCastVar.value.foreach(line => println(line))

            streamingContext.start()
            streamingContext.awaitTermination()
        }
    }

这有效：

object BroadcastStreamTest2 {

        def main(args: Array[String]) {
            val sparkConf = new SparkConf()
            val streamingContext = new StreamingContext(sparkConf, batchDuration = Seconds(10))

            val content = new mutable.ArrayBuffer[String]
            (1 to 50).foreach(i => content += "line" + i)

            val broadCastVar = streamingContext.sparkContext.broadcast(content)
            broadCastVar.value.foreach(line => println(line))

            streamingContext.start()
            streamingContext.awaitTermination()
        }
    }

Stacktrace：

16/04/25 10:09:59 ERROR scheduler.TaskSetManager: Task 0 in stage 0.0 failed 4 times; aborting job
Exception in thread "main" org.apache.spark.SparkException: Job aborted due to stage failure: Task 0 in stage 0.0 failed 4 times, most recent failure: Lost task 0.3 in stage 0.0 (TID 6, n525.hadoop.mxint.net): java.io.IOException: java.lang.ClassCastException: cannot assign instance of scala.Some to field org.apache.spark.Accumulable.name of type scala.Option in instance of org.apache.spark.Accumulator
        at org.apache.spark.util.Utils$.tryOrIOException(Utils.scala:1208)
        at org.apache.spark.Accumulable.readObject(Accumulators.scala:151)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1017)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1893)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
        at scala.collection.immutable.$colon$colon.readObject(List.scala:362)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1017)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1893)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
        at org.apache.spark.serializer.JavaDeserializationStream.readObject(JavaSerializer.scala:76)
        at org.apache.spark.serializer.JavaSerializerInstance.deserialize(JavaSerializer.scala:115)
        at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:194)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassCastException: cannot assign instance of scala.Some to field org.apache.spark.Accumulable.name of type scala.Option in instance of org.apache.spark.Accumulator
        at java.io.ObjectStreamClass$FieldReflector.setObjFieldValues(ObjectStreamClass.java:2083)
        at java.io.ObjectStreamClass.setObjFieldValues(ObjectStreamClass.java:1261)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1996)
        at java.io.ObjectInputStream.defaultReadObject(ObjectInputStream.java:500)
        at org.apache.spark.Accumulable$$anonfun$readObject$1.apply$mcV$sp(Accumulators.scala:152)
        at org.apache.spark.util.Utils$.tryOrIOException(Utils.scala:1205)
        ... 30 more

Driver stacktrace:
        at org.apache.spark.scheduler.DAGScheduler.org$apache$spark$scheduler$DAGScheduler$$failJobAndIndependentStages(DAGScheduler.scala:1431)
        at org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1419)
        at org.apache.spark.scheduler.DAGScheduler$$anonfun$abortStage$1.apply(DAGScheduler.scala:1418)
        at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
        at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47)
        at org.apache.spark.scheduler.DAGScheduler.abortStage(DAGScheduler.scala:1418)
        at org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskSetFailed$1.apply(DAGScheduler.scala:799)
        at org.apache.spark.scheduler.DAGScheduler$$anonfun$handleTaskSetFailed$1.apply(DAGScheduler.scala:799)
        at scala.Option.foreach(Option.scala:236)
        at org.apache.spark.scheduler.DAGScheduler.handleTaskSetFailed(DAGScheduler.scala:799)
        at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.doOnReceive(DAGScheduler.scala:1640)
        at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.onReceive(DAGScheduler.scala:1599)
        at org.apache.spark.scheduler.DAGSchedulerEventProcessLoop.onReceive(DAGScheduler.scala:1588)
        at org.apache.spark.util.EventLoop$$anon$1.run(EventLoop.scala:48)
        at org.apache.spark.scheduler.DAGScheduler.runJob(DAGScheduler.scala:620)
        at org.apache.spark.SparkContext.runJob(SparkContext.scala:1843)
        at org.apache.spark.SparkContext.runJob(SparkContext.scala:1856)
        at org.apache.spark.SparkContext.runJob(SparkContext.scala:1869)
        at org.apache.spark.SparkContext.runJob(SparkContext.scala:1940)
        at org.apache.spark.rdd.RDD$$anonfun$collect$1.apply(RDD.scala:927)
        at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:150)
        at org.apache.spark.rdd.RDDOperationScope$.withScope(RDDOperationScope.scala:111)
        at org.apache.spark.rdd.RDD.withScope(RDD.scala:316)
        at org.apache.spark.rdd.RDD.collect(RDD.scala:926)
        at net.meetrics.dada.streaming.application.BroadcastStreamTest1$.main(BroadcastStreamTest1.scala:14)
        at net.meetrics.dada.streaming.application.BroadcastStreamTest1.main(BroadcastStreamTest1.scala)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at org.apache.spark.deploy.SparkSubmit$.org$apache$spark$deploy$SparkSubmit$$runMain(SparkSubmit.scala:731)
        at org.apache.spark.deploy.SparkSubmit$.doRunMain$1(SparkSubmit.scala:181)
        at org.apache.spark.deploy.SparkSubmit$.submit(SparkSubmit.scala:206)
        at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:121)
        at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
Caused by: java.io.IOException: java.lang.ClassCastException: cannot assign instance of scala.Some to field org.apache.spark.Accumulable.name of type scala.Option in instance of org.apache.spark.Accumulator
        at org.apache.spark.util.Utils$.tryOrIOException(Utils.scala:1208)
        at org.apache.spark.Accumulable.readObject(Accumulators.scala:151)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1017)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1893)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
        at scala.collection.immutable.$colon$colon.readObject(List.scala:362)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:606)
        at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:1017)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1893)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1990)
        at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1915)
        at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1798)
        at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1350)
        at java.io.ObjectInputStream.readObject(ObjectInputStream.java:370)
        at org.apache.spark.serializer.JavaDeserializationStream.readObject(JavaSerializer.scala:76)
        at org.apache.spark.serializer.JavaSerializerInstance.deserialize(JavaSerializer.scala:115)
        at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:194)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
        at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.ClassCastException: cannot assign instance of scala.Some to field org.apache.spark.Accumulable.name of type scala.Option in instance of org.apache.spark.Accumulator
        at java.io.ObjectStreamClass$FieldReflector.setObjFieldValues(ObjectStreamClass.java:2083)
        at java.io.ObjectStreamClass.setObjFieldValues(ObjectStreamClass.java:1261)
        at java.io.ObjectInputStream.defaultReadFields(ObjectInputStream.java:1996)
        at java.io.ObjectInputStream.defaultReadObject(ObjectInputStream.java:500)
        at org.apache.spark.Accumulable$$anonfun$readObject$1.apply$mcV$sp(Accumulators.scala:152)
        at org.apache.spark.util.Utils$.tryOrIOException(Utils.scala:1205)
        ... 30 more

1 回答

1
原因是我提供的jar文件存在某种冲突 .

没有设定
```
spark.executor.userClassPathFirst=true
```
它工作，不幸的是我找不到问题的确切原因 .
回复于 2024-04-29T15:57:06+08:00

Spark Streaming：广播变量，java.lang.ClassCastException

这不起作用：

这有效：

Stacktrace：

1 回答

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