kstreams对两个字段进行分组，以获得计数

import org.apache.kafka.streams.KafkaStreams;
import org.apache.kafka.streams.StreamsBuilder;
import org.apache.kafka.streams.kstream.KStream;
import org.apache.kafka.streams.kstream.KGroupedStream;
import org.apache.kafka.streams.kstream.Materialized;
import org.apache.kafka.streams.kstream.Serialized;
import org.apache.kafka.streams.kstream.TimeWindows;
import org.apache.kafka.streams.kstream.Windowed;

import java.time.Duration;

public class KStreamsExample {
    public static void main(String[] args) {
        // 创建StreamsBuilder对象
        StreamsBuilder builder = new StreamsBuilder();

        // 创建一个KStream对象，从指定的topic读取数据
        KStream<String, String> stream = builder.stream("input-topic");

        // 使用groupBy操作符对两个字段进行分组
        KGroupedStream<String, String> groupedStream = stream.groupBy((key, value) -> value.split(",")[0] + "-" + value.split(",")[1]);

        // 对分组后的数据进行计数
        groupedStream.count(Materialized.as("count-store"));

        // 创建KafkaStreams对象并启动应用程序
        KafkaStreams streams = new KafkaStreams(builder.build(), config);
        streams.start();
    }
}