Spark经典案之求最大最小值

数据准备
eightteen_a.txt
102
10
39
109
200
11
3
90
28
eightteen_b.txt
5
2
30
838
10005
package ClassicCase

import org.apache.spark.{SparkConf, SparkContext}

/**

• 业务场景：求最大最小值
• Created by YJ on 2017/2/8.
  */

object case5 {
def main(args: Array[String]): Unit = {
val conf = new SparkConf().setMaster("local").setAppName("reduce")
val sc = new SparkContext(conf)
sc.setLogLevel("ERROR")
val fifth = sc.textFile("hdfs://192.168.109.130:8020//user/flume/ClassicCase/case5/*", 2)
val res = fifth.filter(_.trim().length>0).map(line => ("key",line.trim.toInt)).groupByKey().map(x => {
var min = Integer.MAX_VALUE
var max = Integer.MIN_VALUE
for(num <- x._2){
if(num>max){
max = num
}
if(num<min){
min = num
}
}
(max,min)
}).collect.foreach(x => {
println("max\t"+x._1)
println("min\t"+x._2)
})
}

}

方法2
package com.neusoft

import org.apache.spark.{SparkConf, SparkContext}

/**

• Created by Administrator on 2019/3/4.
  */
  object FileMaxMin {
  def main(args: Array[String]): Unit = {
  val sparkConf = new SparkConf().setAppName("FileOrder").setMaster("local")

  val sc = new SparkContext(sparkConf)

  val rdd = sc.textFile("demo4/*")
  //key,list(102,10,39,......)
  rdd.filter(_.length > 0).map(x => ("key",x.toInt)).groupByKey().map(x => {
  println("max:" + x._2.max)
  println("max:" + x._2.min)
  }).collect()

}
}

结果输出
max 10005
min 2