java如何在没有“changelog主题”的情况下加入KStream和KTable

Question

我加入了KStream和KTable。下面是我的代码

StreamsBuilder builder = new StreamsBuilder();
KTable<String, String> addressTable = builder.table(ADDRESS_TABLE);
KStream<String, String> orderStream = builder.stream(ORDER_STREAM);
orderStream.join(addressTable, 
        (order, address) -> order + " send to " + address)
        .to(ORDER_JOIN_STREAM);

KafkaStreams streams;
streams = new KafkaStreams(builder.build(), props);
streams.start();

执行此代码后，将创建一个新主题

$ ./kafka-topics.sh --zookeeper localhost:2181 --list
__consumer_offsets
order-join-application3-address-store-name-changelog
address
order

没有“~~~~~~~~~~~~~~~~~~~~~~日志”主题，我如何执行代码

• 代理版本：0.11.0.2
• 流版本：2.7.0

Answer 1

我不确定这是否可能，因为

In the Kafka Streams DSL, an input stream of an aggregation operation can be a KStream or a KTable, but the output stream will always be a KTable.

从Kafka aggregations中提取，它也使用流DSL，如Kafka join。基本上，Kafka join所做的是在他们从here调用“changelog stream”的KTable上执行KStream的查找

KStream-KTable joins are always non-windowed joins. They allow you to perform table lookups against a KTable (changelog stream) upon receiving a new record from the KStream (record stream). An example use case would be to enrich a stream of user activities (KStream) with the latest user profile information (KTable).