集成 - Apache Flink + Spring Boot答案

【问题标题】：Integration - Apache Flink + Spring Boot集成 - Apache Flink + Spring Boot
【发布时间】：2018-01-04 16:27:14
【问题描述】：

我正在测试 Apache Flink 和 Spring Boot 之间的集成，在 IDE 上运行它们很好，但是当我尝试在 Apache Flink Cluster 上运行时，我遇到了一个与 ClassLoader 相关的异常。

这些类真的很简单：

BootFlinkApplication

@SpringBootApplication
@ComponentScan("com.example.demo")
public class BootFlinkApplication {

    public static void main(String[] args) {
        System.out.println("some test");
        SpringApplication.run(BootFlinkApplication.class, args);
    }
}

FlinkTest

@Service
public class FlinkTest {
    @PostConstruct
    public void init() {
        StreamExecutionEnvironment see = StreamExecutionEnvironment.getExecutionEnvironment();

        see.fromElements(1, 2, 3, 4)
            .filter(new RemoveNumber3Filter()).print();

        try {
            see.execute();
        } catch (Exception e) {
            System.out.println("Error executing flink job: " + e.getMessage());
        }
    }
}

移除Number3Filter

public class RemoveNumber3Filter implements FilterFunction<Integer> {

    @Override
    public boolean filter(Integer i) throws Exception {
        return i != 3;
    }

}

例外：

Caused by: org.apache.flink.runtime.client.JobExecutionException: Job execution failed.
        at org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$6.apply$mcV$sp(JobManager.scala:897)
        at org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$6.apply(JobManager.scala:840)
        at org.apache.flink.runtime.jobmanager.JobManager$$anonfun$handleMessage$1$$anonfun$applyOrElse$6.apply(JobManager.scala:840)
        at scala.concurrent.impl.Future$PromiseCompletingRunnable.liftedTree1$1(Future.scala:24)
        at scala.concurrent.impl.Future$PromiseCompletingRunnable.run(Future.scala:24)
        at akka.dispatch.TaskInvocation.run(AbstractDispatcher.scala:39)
        at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:415)
        at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
        at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
        at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
        at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
    Caused by: org.apache.flink.streaming.runtime.tasks.StreamTaskException: Cannot load user class: com.example.demo.RemoveNumber3Filter
    ClassLoader info: URL ClassLoader:
        file: '/tmp/blobStore-850f3189-807e-4f8d-a8a6-3bd3c1bd76b4/job_eb93b239080b4d4e09f10f1e3605744d/blob_p-5fd56f3348976c0d333d680fde4a79573c21cd40-48ac0995eee11f38ce3ff4f890102af8' (valid JAR)
    Class not resolvable through given classloader.
        at org.apache.flink.streaming.api.graph.StreamConfig.getStreamOperator(StreamConfig.java:232)
        at org.apache.flink.streaming.runtime.tasks.OperatorChain.createChainedOperator(OperatorChain.java:355)
        at org.apache.flink.streaming.runtime.tasks.OperatorChain.createOutputCollector(OperatorChain.java:282)
        at org.apache.flink.streaming.runtime.tasks.OperatorChain.<init>(OperatorChain.java:126)
        at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:231)
        at org.apache.flink.runtime.taskmanager.Task.run(Task.java:718)
        at java.lang.Thread.run(Thread.java:748)

【问题讨论】：

你看过这个页面吗？ ci.apache.org/projects/flink/flink-docs-release-1.3/monitoring/…
是的，我看到了，但没有多大帮助...
您能否检查RemoveNumber3Filter 是否包含在jar blob_p-5fd56f3348976c0d333d680fde4a79573c21cd40-48ac0995eee11f38ce3ff4f890102af8 或您用于启动应用程序的jar 中。
是的，它是......问题是spring boot创建的jar有文件夹BOOT-INF/classes里面的类

标签： spring-boot apache-flink

【解决方案1】：

您可能使用 Spring Boot Maven 插件 (https://docs.spring.io/spring-boot/docs/current/reference/html/build-tool-plugins-maven-plugin.html) 重新打包您的 Jar 以生成可执行 jar，但是，它使用 Apache Flink 的内部类加载器不支持的自定义引导布局。您尝试部署的文件旁边应该有一个原始 jar 文件（.jar.original），您可以将其用于在 Flink 集群上进行部署。

作为替代方案，您可以使用其他方式生成包含所有依赖项的 Jar，例如 maven-shade (https://maven.apache.org/plugins/maven-shade-plugin/)

【讨论】：