多对一记录卡夫卡流

Question

我希望每条消息将许多记录变成一个。我尝试了许多类似自定义归约和聚合器的方法，但是它们仍然可以发送一对一的记录。例如，我想将许多字符串转换为一个字符串。如果我的信息流中的消息具有相同的键，但是值不同，则分别是“ the”，“ sky”，“ is”，“ blue”，那么我想在新主题“ the，sky，是蓝色。”相反，我得到的是4条消息“ the”，“ the，sky”，“ the，sky，is”，“ the，sky，is，blue”。当我向kafka用户发送第二条消息时，它将连接到先前的聚合上，最终我收到此消息“ the，sky，is，blue，the，sky，is，blue，”

我还尝试使用自定义storebuilder并更改许多设置以查看是否可以执行任何操作。

     Map<String, String> changelogConfig = new HashMap<>();
            changelogConfig.put("message.down.conversion.enable", "true");
            changelogConfig.put("flush.messages", "0");
            changelogConfig.put("flush.ms", "0");

     StoreBuilder<KeyValueStore<String, String>> aggStoreSupplier = Stores.keyValueStoreBuilder(
                    Stores.persistentKeyValueStore("AggStore"),
                    Serdes.String(),
                    Serdes.String())
                    .withLoggingEnabled(changelogConfig);

     KStream<String, String> results = source // single message get processed and eventually i get these string results I need to concatenate
            .groupByKey() // this kgroupedstream has the N records, which was how many were sent in the message
            .reduce(new Reducer<String>() {
                        @Override
                        public String apply(String aggValue, String value) {
                            return value + "," + aggValue;
                        }
                    }, Materialized.as("AggStore"))
                    .toStream();

     results.to("results", Produced.with(Serdes.String(), Serdes.String()));
     final Topology topology = builder.build(); // to describe topology
     System.out.println(topology.describe()); // to print description
     final KafkaStreams streams = new KafkaStreams(topology, props);

     final CountDownLatch latch = new CountDownLatch(1);
     // attach shutdown handler to catch control-c
     Runtime.getRuntime().addShutdownHook(new Thread("streams-shutdown-hook") {
       @Override
       public void run() {
                streams.close();
                latch.countDown();
            }
       });

       try {
            streams.cleanUp();
            streams.start();
            latch.await();
       } catch (Throwable e) {
            System.exit(1);
       }
     System.exit(0);