上图意思：每隔2秒统计前3秒的数据

slideDuration: 2

windowDuration: 3

例子:

import org.apache.kafka.common.serialization.StringDeserializer import org.apache.spark.SparkConf import org.apache.spark.streaming.dstream.DStream import org.apache.spark.streaming.{Seconds, StreamingContext} import org.apache.spark.streaming.kafka010.ConsumerStrategies.Subscribe import org.apache.spark.streaming.kafka010.KafkaUtils import org.apache.spark.streaming.kafka010.LocationStrategies.PreferConsistent object WindowStreaming { def main(args: Array[String]): Unit = { val conf = new SparkConf().setAppName("KafkaDirect").setMaster("local[1]") val ssc = new StreamingContext(conf, Seconds(1)) val kafkaMapParams = Map[String, Object]( "bootstrap.servers" -> "192.168.1.151:9092,192.168.1.152:9092,192.168.1.153:9092", "key.deserializer" -> classOf[StringDeserializer], "value.deserializer" -> classOf[StringDeserializer], "group.id" -> "g1", "auto.offset.reset" -> "latest", //earliest|latest "enable.auto.commit" -> (false: java.lang.Boolean) ) val topicsSet = Set("ScalaTopic") val kafkaStream = KafkaUtils.createDirectStream[String, String]( ssc, PreferConsistent, Subscribe[String, String](topicsSet, kafkaMapParams) ) val finalResultRDD: DStream[(Int, String)] = kafkaStream.flatMap(row => row.value().split(" ")) .map((_, 1)).reduceByKeyAndWindow((x: Int, y: Int) => x + y, Seconds(3), Seconds(2)) .transform(rdd => rdd.map(tuple => (tuple._2, tuple._1)) .sortByKey(false).map(tuple => (tuple._1, tuple._2)) ) finalResultRDD.print() ssc.start() ssc.awaitTermination() } }

运行功效：