Question

我有一个flink jar，它在弹性和cassandra上接收一个可序列化数据类型的数据流，其中包含一个与独立上下文不同的beahaviour。我已经阅读了关于与Flink流程的netty冲突，我将其从pom文件中排除，但它随后被包含在包中有什么建议吗？

这是一个例外：

// Saving result to variable (as anytime before)
// Note that I have changed "int" to "var", which simplifies the code,
// as You don't have to take care of "what type will the result be"
// usage is really common with LINQ also
var result = 

// calling method Sum() on the productList
productList.Sum()

// Sum will take each object in the collection and put it as a parameter called "nProduct"
// now the "=>" is something called Lambda syntax,
// that allows take paremeters from the left side and use them in code on the right side.
// left side is instance of "Product" class named as "nProduct"
Sum(nProduct => ... )

// ... is replaced with "nProduct.Price",
// which is selector that tells "make the sum of property "Price"
Sum(nProduct => nProduct.Price)

// In similar manner works other aggregate functions
var max = productList.Max(prod => prod.Price);
var min = productList.Min(prod => prod.Price);
var avg = productList.Average(prod => prod.Price);

这是pom文件：

java.lang.ClassCastException: io.netty.channel.epoll.EpollEventLoopGroup cannot be cast to io.netty.channel.EventLoopGroup
    at com.datastax.driver.core.NettyUtil.newEventLoopGroupInstance(NettyUtil.java:134)
    at com.datastax.driver.core.NettyOptions.eventLoopGroup(NettyOptions.java:99)
    at com.datastax.driver.core.Connection$Factory.<init>(Connection.java:774)
    at com.datastax.driver.core.Cluster$Manager.init(Cluster.java:1446)
    at com.datastax.driver.core.Cluster.init(Cluster.java:159)
    at com.datastax.driver.core.Cluster.connectAsync(Cluster.java:330)
    at com.datastax.driver.core.Cluster.connectAsync(Cluster.java:305)
    at com.datastax.driver.core.Cluster.connect(Cluster.java:247)
    at it.almaviva.wtf.mms.integratemobilitystatusevent.repository.cassandra.ScheduledEventRepositoryImpl.findProgrammed(ScheduledEventRepositoryImpl.java:51)
    at it.almaviva.wtf.mms.integratemobilitystatusevent.transformation.ObservedEventDelayProcessFunction.loadScheduledEvents(ObservedEventDelayProcessFunction.java:368)
    at it.almaviva.wtf.mms.integratemobilitystatusevent.transformation.ObservedEventDelayProcessFunction.processElement(ObservedEventDelayProcessFunction.java:64)
    at it.almaviva.wtf.mms.integratemobilitystatusevent.transformation.ObservedEventDelayProcessFunction.processElement(ObservedEventDelayProcessFunction.java:1)
    at org.apache.flink.streaming.api.operators.KeyedProcessOperator.processElement(KeyedProcessOperator.java:94)
    at org.apache.flink.streaming.runtime.io.StreamInputProcessor.processInput(StreamInputProcessor.java:207)
    at org.apache.flink.streaming.runtime.tasks.OneInputStreamTask.run(OneInputStreamTask.java:69)
    at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:264)
    at org.apache.flink.runtime.taskmanager.Task.run(Task.java:718)
    at java.lang.Thread.run(Thread.java:748)
    Suppressed: java.lang.NullPointerException
        at com.datastax.driver.core.Cluster$Manager.close(Cluster.java:1676)
        at com.datastax.driver.core.Cluster$Manager.access$200(Cluster.java:1354)
        at com.datastax.driver.core.Cluster.closeAsync(Cluster.java:566)
        at com.datastax.driver.core.Cluster.close(Cluster.java:578)
        at it.almaviva.wtf.mms.integratemobilitystatusevent.repository.cassandra.ScheduledEventRepositoryImpl.findProgrammed(ScheduledEventRepositoryImpl.java:68)

Answer 1

我将参数添加到conf / flink.yaml并且很棒，它就像一个魅力!!!! 我和同事一起检查了pom文件。 :) Thankkkss

REF： https://docs.datastax.com/en/developer/java-driver-dse/1.4/faq/ https://ci.apache.org/projects/flink/flink-docs-release-1.2/setup/config.html#runtime-algorithms

Answer 2

您可以通过添加JVM参数-Dcom.datastax.driver.FORCE_NIO=true来禁用Netty的本机epoll传输并强制执行默认的基于NIO的传输。
（https://docs.datastax.com/en/developer/java-driver-dse/1.4/faq/#what-is-netty-s-native-epoll-transport-and-how-do-i-enable-or-disable-it）

在Flink中，您必须使用该参数将env.java.opts设置为conf/flink-conf.yaml （https://ci.apache.org/projects/flink/flink-docs-release-1.4/ops/config.html#common-options）

java.lang.ClassCastException：Netty在Flink上执行jar时失败

2 个答案: