怎样做网站建设的程序谷歌浏览器app

Spark-Streaming概述

DStream实操

案例一：WordCount案例

需求：使用 netcat 工具向 9999 端口不断的发送数据，通过 SparkStreaming 读取端口数据并统计不同单词出现的次数

实验步骤：

1. 添加依赖

<dependency>
    <groupId>org.apache.spark</groupId>
    <artifactId>spark-streaming_2.12</artifactId>
    <version>3.0.0</version>
</dependency>

1. 编写代码

val sparkConf = new SparkConf().setMaster("local[*]").setAppName("streaming")
val ssc = new StreamingContext(sparkConf,Seconds(3))

val lineStreams = ssc.socketTextStream("node01",9999)
val wordStreams = lineStreams.flatMap(_.split(" "))
val wordAndOneStreams = wordStreams.map((_,1))
val wordAndCountStreams = wordAndOneStreams.reduceByKey(_+_)
wordAndCountStreams.print()

ssc.start()
ssc.awaitTermination()

1. 启动netcat发送数据

nc -lk 9999

结果：