您好！ 看起来这个问题与 FLINK-35066[1] 有关，该问题描述了在 IterationBody 内实现自定义的RichCoProcessFunction 或 CoFlatMapFunction 算子时遇到的拆包问题，可以追溯到这个[2]邮件列表中的问题报告。看起来这个问题也同样影响您使用的 RichCoMapFunction 算子。 该问题已被此 Pull Request[3] 解决，并已合入 master 主分支。按照文档[4]尝试在本地编译 2.4-SNAPSHOT 快照版本并执行您的代码，看起来能够正常工作。 鉴于这是一个 Flink ML 2.3 版本中的已知问题，您可以尝试在本地编译自己的快照版本，或是等待 Flink ML 2.4 的发布并更新依赖版本。 祝好！
Regards, yux [1] https://issues.apache.org/jira/browse/FLINK-35066 [2] https://lists.apache.org/thread/bgkw1g2tdgnp1xy1clsqtcfs3h18pkd6 [3] https://github.com/apache/flink-ml/pull/260 [4] https://github.com/apache/flink-ml#building-the-project De : w...@shanghaitech.edu.cn <w...@shanghaitech.edu.cn> Date : vendredi, 31 mai 2024 à 17:34 À : user-zh@flink.apache.org <user-zh@flink.apache.org> Objet : 【求助】关于 Flink ML 迭代中使用keyBy算子报错 尊敬的Flink开发者您好， 我在使用Flink ML模块的迭代功能时遇到了一个问题，当我在迭代体内使用keyBy算子时，会出现以下错误： Caused by: java.lang.ClassCastException: org.apache.flink.iteration.IterationRecord cannot be cast to java.lang.String 我已经查阅文档，但还是没有头绪，所以希望能得到您的帮助，非常感谢。 我已在下方附上了最小可复现代码、报错信息以及我的运行环境信息。 以下是最小复现代码 ~~~java package myflinkml; import org.apache.flink.iteration.DataStreamList; import org.apache.flink.iteration.IterationBody; import org.apache.flink.iteration.IterationBodyResult; import org.apache.flink.iteration.Iterations; import org.apache.flink.streaming.api.datastream.DataStream; import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator; import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment; import org.apache.flink.streaming.api.functions.co.RichCoMapFunction; public class BugDemo { public static void main(String[] args) throws Exception { StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment(); env.setParallelism(1); DataStream<String> textStream = env.fromElements("Hello", "Flink"); DataStream<Integer> intStream = env.fromElements(1, 2, 3); Iterations.iterateUnboundedStreams( DataStreamList.of(intStream), DataStreamList.of(textStream), new Body() ).get(0).print(); env.execute(); } private static class Body implements IterationBody { @Override public IterationBodyResult process(DataStreamList dsl1, DataStreamList dsl2) { DataStream<Integer> intStream = dsl1.get(0); DataStream<String> textStream = dsl2.get(0); // 迭代输出流 DataStream<String> outStream = textStream .connect(intStream) .keyBy(x -> 1, x -> 1) // 添加这行就报错!! .map(new RichCoMapFunction<String, Integer, String>() { @Override public String map1(String value) throws Exception { return "Strings: " + value; } @Override public String map2(Integer value) throws Exception { return "Integer: " + value; } }); // 迭代反馈流 SingleOutputStreamOperator<Integer> feedBackStream = intStream.map(x -> x - 1).filter(x -> x > 0); return new IterationBodyResult(DataStreamList.of(feedBackStream), DataStreamList.of(outStream)); } } } ~~~ 运行报错输出： Exception in thread "main" org.apache.flink.runtime.client.JobExecutionException: Job execution failed. at org.apache.flink.runtime.jobmaster.JobResult.toJobExecutionResult(JobResult.java:144) at org.apache.flink.runtime.minicluster.MiniClusterJobClient.lambda$getJobExecutionResult$3(MiniClusterJobClient.java:141) at java.util.concurrent.CompletableFuture.uniApply(CompletableFuture.java:616) at java.util.concurrent.CompletableFuture$UniApply.tryFire(CompletableFuture.java:591) at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:488) at java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:1975) at org.apache.flink.runtime.rpc.akka.AkkaInvocationHandler.lambda$invokeRpc$1(AkkaInvocationHandler.java:267) at java.util.concurrent.CompletableFuture.uniWhenComplete(CompletableFuture.java:774) at java.util.concurrent.CompletableFuture$UniWhenComplete.tryFire(CompletableFuture.java:750) at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:488) at java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:1975) at org.apache.flink.util.concurrent.FutureUtils.doForward(FutureUtils.java:1300) at org.apache.flink.runtime.concurrent.akka.ClassLoadingUtils.lambda$null$1(ClassLoadingUtils.java:93) at org.apache.flink.runtime.concurrent.akka.ClassLoadingUtils.runWithContextClassLoader(ClassLoadingUtils.java:68) at org.apache.flink.runtime.concurrent.akka.ClassLoadingUtils.lambda$guardCompletionWithContextClassLoader$2(ClassLoadingUtils.java:92) at java.util.concurrent.CompletableFuture.uniWhenComplete(CompletableFuture.java:774) at java.util.concurrent.CompletableFuture$UniWhenComplete.tryFire(CompletableFuture.java:750) at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:488) at java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:1975) at org.apache.flink.runtime.concurrent.akka.AkkaFutureUtils$1.onComplete(AkkaFutureUtils.java:47) at akka.dispatch.OnComplete.internal(Future.scala:300) at akka.dispatch.OnComplete.internal(Future.scala:297) at akka.dispatch.japi$CallbackBridge.apply(Future.scala:224) at akka.dispatch.japi$CallbackBridge.apply(Future.scala:221) at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:64) at org.apache.flink.runtime.concurrent.akka.AkkaFutureUtils$DirectExecutionContext.execute(AkkaFutureUtils.java:65) at scala.concurrent.impl.CallbackRunnable.executeWithValue(Promise.scala:72) at scala.concurrent.impl.Promise$DefaultPromise.$anonfun$tryComplete$1(Promise.scala:288) at scala.concurrent.impl.Promise$DefaultPromise.$anonfun$tryComplete$1$adapted(Promise.scala:288) at scala.concurrent.impl.Promise$DefaultPromise.tryComplete(Promise.scala:288) at akka.pattern.PromiseActorRef.$bang(AskSupport.scala:622) at akka.pattern.PipeToSupport$PipeableFuture$$anonfun$pipeTo$1.applyOrElse(PipeToSupport.scala:24) at akka.pattern.PipeToSupport$PipeableFuture$$anonfun$pipeTo$1.applyOrElse(PipeToSupport.scala:23) at scala.concurrent.Future.$anonfun$andThen$1(Future.scala:536) at scala.concurrent.impl.Promise.liftedTree1$1(Promise.scala:33) at scala.concurrent.impl.Promise.$anonfun$transform$1(Promise.scala:33) at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:64) at akka.dispatch.BatchingExecutor$AbstractBatch.processBatch(BatchingExecutor.scala:63) at akka.dispatch.BatchingExecutor$BlockableBatch.$anonfun$run$1(BatchingExecutor.scala:100) at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23) at scala.concurrent.BlockContext$.withBlockContext(BlockContext.scala:85) at akka.dispatch.BatchingExecutor$BlockableBatch.run(BatchingExecutor.scala:100) at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:49) at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(ForkJoinExecutorConfigurator.scala:48) at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289) at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056) at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1692) at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:175) Caused by: org.apache.flink.runtime.JobException: Recovery is suppressed by NoRestartBackoffTimeStrategy at org.apache.flink.runtime.executiongraph.failover.flip1.ExecutionFailureHandler.handleFailure(ExecutionFailureHandler.java:139) at org.apache.flink.runtime.executiongraph.failover.flip1.ExecutionFailureHandler.getFailureHandlingResult(ExecutionFailureHandler.java:83) at org.apache.flink.runtime.scheduler.DefaultScheduler.recordTaskFailure(DefaultScheduler.java:258) at org.apache.flink.runtime.scheduler.DefaultScheduler.handleTaskFailure(DefaultScheduler.java:249) at org.apache.flink.runtime.scheduler.DefaultScheduler.onTaskFailed(DefaultScheduler.java:242) at org.apache.flink.runtime.scheduler.SchedulerBase.onTaskExecutionStateUpdate(SchedulerBase.java:748) at org.apache.flink.runtime.scheduler.SchedulerBase.updateTaskExecutionState(SchedulerBase.java:725) at org.apache.flink.runtime.scheduler.SchedulerNG.updateTaskExecutionState(SchedulerNG.java:80) at org.apache.flink.runtime.jobmaster.JobMaster.updateTaskExecutionState(JobMaster.java:479) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.apache.flink.runtime.rpc.akka.AkkaRpcActor.lambda$handleRpcInvocation$1(AkkaRpcActor.java:309) at org.apache.flink.runtime.concurrent.akka.ClassLoadingUtils.runWithContextClassLoader(ClassLoadingUtils.java:83) at org.apache.flink.runtime.rpc.akka.AkkaRpcActor.handleRpcInvocation(AkkaRpcActor.java:307) at org.apache.flink.runtime.rpc.akka.AkkaRpcActor.handleRpcMessage(AkkaRpcActor.java:222) at org.apache.flink.runtime.rpc.akka.FencedAkkaRpcActor.handleRpcMessage(FencedAkkaRpcActor.java:84) at org.apache.flink.runtime.rpc.akka.AkkaRpcActor.handleMessage(AkkaRpcActor.java:168) at akka.japi.pf.UnitCaseStatement.apply(CaseStatements.scala:24) at akka.japi.pf.UnitCaseStatement.apply(CaseStatements.scala:20) at scala.PartialFunction.applyOrElse(PartialFunction.scala:127) at scala.PartialFunction.applyOrElse$(PartialFunction.scala:126) at akka.japi.pf.UnitCaseStatement.applyOrElse(CaseStatements.scala:20) at scala.PartialFunction$OrElse.applyOrElse(PartialFunction.scala:175) at scala.PartialFunction$OrElse.applyOrElse(PartialFunction.scala:176) at scala.PartialFunction$OrElse.applyOrElse(PartialFunction.scala:176) at akka.actor.Actor.aroundReceive(Actor.scala:537) at akka.actor.Actor.aroundReceive$(Actor.scala:535) at akka.actor.AbstractActor.aroundReceive(AbstractActor.scala:220) at akka.actor.ActorCell.receiveMessage(ActorCell.scala:579) at akka.actor.ActorCell.invoke(ActorCell.scala:547) at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:270) at akka.dispatch.Mailbox.run(Mailbox.scala:231) at akka.dispatch.Mailbox.exec(Mailbox.scala:243) ... 4 more Caused by: java.lang.ClassCastException: org.apache.flink.iteration.IterationRecord cannot be cast to java.lang.String at org.apache.flink.streaming.api.operators.AbstractStreamOperator.setKeyContextElement(AbstractStreamOperator.java:502) at org.apache.flink.streaming.api.operators.AbstractStreamOperator.setKeyContextElement1(AbstractStreamOperator.java:478) at org.apache.flink.iteration.operator.allround.AbstractAllRoundWrapperOperator.setKeyContextElement1(AbstractAllRoundWrapperOperator.java:203) at org.apache.flink.streaming.runtime.io.RecordProcessorUtils.lambda$getRecordProcessor1$1(RecordProcessorUtils.java:87) at org.apache.flink.streaming.runtime.io.StreamTwoInputProcessorFactory$StreamTaskNetworkOutput.emitRecord(StreamTwoInputProcessorFactory.java:254) at org.apache.flink.streaming.runtime.io.AbstractStreamTaskNetworkInput.processElement(AbstractStreamTaskNetworkInput.java:146) at org.apache.flink.streaming.runtime.io.AbstractStreamTaskNetworkInput.emitNext(AbstractStreamTaskNetworkInput.java:110) at org.apache.flink.streaming.runtime.io.StreamOneInputProcessor.processInput(StreamOneInputProcessor.java:65) at org.apache.flink.streaming.runtime.io.StreamMultipleInputProcessor.processInput(StreamMultipleInputProcessor.java:85) at org.apache.flink.streaming.runtime.tasks.StreamTask.processInput(StreamTask.java:550) at org.apache.flink.streaming.runtime.tasks.mailbox.MailboxProcessor.runMailboxLoop(MailboxProcessor.java:231) at org.apache.flink.streaming.runtime.tasks.StreamTask.runMailboxLoop(StreamTask.java:839) at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:788) at org.apache.flink.runtime.taskmanager.Task.runWithSystemExitMonitoring(Task.java:952) at org.apache.flink.runtime.taskmanager.Task.restoreAndInvoke(Task.java:931) at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:745) at org.apache.flink.runtime.taskmanager.Task.run(Task.java:562) at java.lang.Thread.run(Thread.java:750) Process finished with exit code 1 运行环境： java 1.8 flink 1.17.1 flink-ml-uber-1.17 2.3.0 再次感谢。 附件为完整maven项目代码
