Spark Streaming之旅

1. 打开spark-shell

2. 建立StreamingContext

import org.apache.spark.streaming._
import org.apache.spark.streaming.StreamingContext._

import org.apache.spark.api.java.function._
import org.apache.spark.streaming._
import org.apache.spark.streaming.api._
// Create a StreamingContext with a local master
val ssc = new StreamingContext(sc, Seconds(1))

3.用StreamingContext建立一个DStream

val lines = ssc.socketTextStream("localhost", 9999)

4.运算

// Split each line into words
val words = lines.flatMap(_.split(" "))

import org.apache.spark.streaming.StreamingContext._
// Count each word in each batch
val pairs = words.map(word => (word, 1))
val wordCounts = pairs.reduceByKey(_ + _)

// Print a few of the counts to the console
wordCounts.print()

5.启动DStream

ssc.start()             // Start the computation
ssc.awaitTermination()  // Wait for the computation to terminate

6.启动一个新控制台，并执行如下命令

$ nc -lk 9999

7.在新控制台上输入任意语句，并在spark-shell窗口观察输出

hello world how are you hello are you there

you are the son of a bitch