统计最长单词

习题 20：统计最长单词

题目：读取文件，找出所有单词中长度最大的值。

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

object TestMaxWord {
  def main(args: Array[String]): Unit = {
    val conf = new SparkConf().setAppName("testmaxnum").setMaster("local[*]")
    val sc = new SparkContext(conf)
    val rddlines = sc.textFile("input/word.txt")
    val rddwords = rddlines.flatMap(line => line.split(" "))
    val rddlen = rddwords.map(word => word.length)
    val maxlen = rddlen.reduce((x, y) => Math.max(x, y))
    println(maxlen)
  }
}