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Posted to user@flink.apache.org by "wanglei2@geekplus.com.cn" <wa...@geekplus.com.cn> on 2020/05/30 08:57:59 UTC

回复: Re: java.lang.AbstractMethodError when implementing KafkaSerializationSchema

It is because the jar conflict and i have fixed it. 

I put  flink-connector-kafka_2.11-1.10.0.jar in the flink lib directory. 
Also in my project pom file has the dependency  flink-connector-kafka and builded as a fat jar

Thanks,
Lei



wanglei2@geekplus.com.cn

 
发件人: Leonard Xu
发送时间: 2020-05-26 15:47
收件人: Aljoscha Krettek
抄送: user
主题: Re: java.lang.AbstractMethodError when implementing KafkaSerializationSchema
Hi,wanglei

I think Aljoscha is wright. Could you post your denpendency list?
Dependency flink-connector-kafka is used in dataStream Application which you should use, dependency flink-sql-connector-kafka is used in Table API & SQL Application. We should only add one of them because the two dependency will conflict.   

Best,
Leonard Xu

在 2020年5月26日,15:02,Aljoscha Krettek <al...@apache.org> 写道:

I think what might be happening is that you're mixing dependencies from the flink-sql-connector-kafka and the proper flink-connector-kafka that should be used with the DataStream API. Could that be the case?

Best,
Aljoscha

On 25.05.20 19:18, Piotr Nowojski wrote:
Hi,
It would be helpful if you could provide full stack trace, what Flink version and which Kafka connector version are you using?
It sounds like either a dependency convergence error (mixing Kafka dependencies/various versions of flink-connector-kafka inside a single job/jar) or some shading issue. Can you check your project for such issues (`mvn dependency:tree` command [1]).
Also what’s a bit suspicious for me is the return type:
Lorg/apache/flink/kafka/shaded/org/apache/kafka/clients/producer/ProducerRecord;
I’m not sure, but I was not aware that we are shading Kafka dependency in our connectors? Are you manually shading something?
Piotrek
[1] https://maven.apache.org/plugins/maven-dependency-plugin/examples/resolving-conflicts-using-the-dependency-tree.html <https://maven.apache.org/plugins/maven-dependency-plugin/examples/resolving-conflicts-using-the-dependency-tree.html>
On 22 May 2020, at 15:34, wanglei2@geekplus.com.cn wrote:


public class MyKafkaSerializationSchema implements KafkaSerializationSchema<Tuple2<String, String>> {
    @Override
    public ProducerRecord<byte[], byte[]> serialize(Tuple2<String, String> o, @Nullable Long aLong) {
        ProducerRecord<byte[], byte[]> record = new ProducerRecord<>(o.f0,
            o.f1.getBytes(StandardCharsets.UTF_8));
        return record;
    }
}
FlinkKafkaProducer<Tuple2<String, String>> producer = new FlinkKafkaProducer<Tuple2<String, String>>(
    "default", new MyKafkaSerializationSchema(),
    prop2,Semantic.EXACTLY_ONCE);

But there's  error when runnng:

java.lang.AbstractMethodError: com.geekplus.flinketl.schema.MyKafkaSerializationSchema.serialize(Ljava/lang/Object;Ljava/lang/Long;)Lorg/apache/flink/kafka/shaded/org/apache/kafka/clients/producer/ProducerRecord;

Any suggestion on this?

Thanks,
Lei
wanglei2@geekplus.com.cn <ma...@geekplus.com.cn>