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SparkStreaming 实现入门WordCount
这是SparkStreaming的基本入门,官网:http://spark.apache.org/docs/2.3.2/streaming-programming-guide.html#a-quick-example
代码如下,在执行前在 deptest22上输入命令 nc -lk 9999
。
import org.apache.spark.SparkContext
import org.apache.spark.sql.SparkSession
import org.apache.spark.streaming.dstream.ReceiverInputDStream
import org.apache.spark.streaming.{Seconds, StreamingContext}
object TestStreamingWC {
def main(args: Array[String]): Unit = {
val spark = SparkSession.builder()
.appName("TestStreamingWC")
.master("local[*]")
.getOrCreate()
val sc: SparkContext = spark.sparkContext
val ssc: StreamingContext = new StreamingContext(sc, Seconds(3))
val lines = ssc.socketTextStream("deptest22", 9999)
val wordCounts = lines.flatMap(_.split(" "))
.map((_, 1)).reduceByKey(_ + _)
wordCounts.print()
ssc.start()
ssc.awaitTermination()
}
}
假如在deptest22输入 hadoop hadoop hadoop hadoop,得到如下结果,说明成功了
-------------------------------------------
Time: 1551329700000 ms
-------------------------------------------
(hadoop,4)
====================================================================
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