Kafka Streams物化商店构建错误 [英] Kafka Streams Materialized Store Build Error

问题描述

我正在尝试在此处构建Materialized.as DSL代码: https://kafka.apache.org/11/javadoc/org/apache/kafka/streams/state/Stores.html

I'm trying to build the Materialized.as DSL code here: https://kafka.apache.org/11/javadoc/org/apache/kafka/streams/state/Stores.html

但是我遇到了错误

incompatible types: org.apache.kafka.common.serialization.Serde<java.lang.Long> cannot be converted to org.apache.kafka.common.serialization.Serde<java.lang.Object>

在线

.withKeySerde(Serdes.Long())

有人知道这里可能出什么问题吗?

Does anyone know what might be wrong here?

final StreamsBuilder builder = new StreamsBuilder();

   KeyValueBytesStoreSupplier storeSupplier = Stores.inMemoryKeyValueStore("mystore");
   KTable<Long,String> dataStore = builder.table(
     "example_stream",
     Materialized.as(storeSupplier)
             .withKeySerde(Serdes.Long())
             .withValueSerde(Serdes.String()));

推荐答案

问题是 builder.table 不知道默认为< Object，Object> 的通用类型.代码>.后来，Serde类型不匹配.您需要指定类似

The problem is that builder.table does not know the generic type defaulting to <Object,Object>. Later, the Serde types don't match. You need to specify the types like

KTable<Long,String> dataStore = builder.<Long,String>table(
    "example_stream",
    Materialized.as(storeSupplier)
        .withKeySerde(Serdes.Long())
        .withValueSerde(Serdes.String()));

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