windows+spark本地运行环境搭建

spark作为一个内存mapreduce框架，速度是hadoop的10倍甚至100倍。windows下可以通过简单设置，搭建本地运行环境。

1、下载spark预编译版本，spark运行环境依赖jdk,scala，这里下载的最新spark版本是2.3，对应jdk1.8+scala2.11.8。

java -version
java version "1.8.0_151"
Java(TM) SE Runtime Environment (build 1.8.0_151-b12)
Java HotSpot(TM) 64-Bit Server VM (build 25.151-b12, mixed mode)

scala -version
Scala code runner version 2.11.7 -- Copyright 2002-2013, LAMP/EPFL  

2、下载hadoop-common-2.2工具包，并设置环境变量HADOOP_HOME,PATH。

如果不下载hadoop-common-2.2并设置环境变量，启动spark-shell时，会报如下错误：

ERROR Shell:397 - Failed to locate the winutils binary in the hadoop binary path
java.io.IOException: Could not locate executable null\bin\winutils.exe in the Hadoop binar
ies.  

hadoop-common包下有bin目录，bin目录中的内容如下：

3、standalone方式启动spark：进入spark-2.3.0-bin-hadoop2.7目录，按住shift，鼠标右键->在此处打开命令窗口。运行bin\spark-shell

启动成功，会进入scala命令行交互界面，然后就可以进行编码了。

scala> val textFile = sc.textFile("helloSpark.txt");
textFile: org.apache.spark.rdd.RDD[String] = helloSpark.txt MapPartitionsRDD[1] at textFil
e at <console>:24

scala> textFile.foreach(println)
sparkui
hello,java
spark
hello,scala
hello,spark

scala> val counts = textFile.flatMap(line=>line.split(",")).map(x=>(x,1)).reduceByKey((x,y
)=>(x+y))
counts: org.apache.spark.rdd.RDD[(String, Int)] = ShuffledRDD[10] at reduceByKey at <conso
le>:25

scala> counts.foreach(println)
(spark,2)
(sparkui,1)
(scala,1)
(hello,3)
(java,1)

scala>  

这里运行一个最简单的wordcount程序，先导入一个文档，文档五行内容，然后运行flatMap(),将文档内容每一行按照逗号分割，然后运行map(),reduceByKey()。