map-reduce的并发执行会导致Class Cast Exceptption

Question

我正在使用hadoop-core-1.2.0。我正在尝试执行8个并发map-reduce作业。
ExecutonService用于提交作业。但是当程序运行时，它会给出以下异常

java.lang.Exception: java.lang.ClassCastException: org.apache.hadoop.mapreduce.lib.input.FileSplit cannot be cast to org.apache.hadoop.mapred.InputSplit
at org.apache.hadoop.mapred.LocalJobRunner$Job.run(LocalJobRunner.java:354)
Caused by: java.lang.ClassCastException: org.apache.hadoop.mapreduce.lib.input.FileSplit cannot be cast to org.apache.hadoop.mapred.InputSplit
at org.apache.hadoop.mapred.MapTask.runOldMapper(MapTask.java:406)
at org.apache.hadoop.mapred.MapTask.run(MapTask.java:366)
at org.apache.hadoop.mapred.LocalJobRunner$Job$MapTaskRunnable.run(LocalJobRunner.java:223)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:439)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:895)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:918)
at java.lang.Thread.run(Thread.java:680)

我在google找不到答案。很少有人遇到同样的问题。根据{{​​3}}，它发生是因为并发调用waitForCompletion。

请帮助!!!

Answer 1

在作业中用org.apache.hadoop.mapred.FileSplit替换FileSplit的导入。