RDD实例

实例一：

teacher.log

http://bigdata.baidu.cn/zhangsan
http://bigdata.baidu.cn/zhangsan
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/wangwu
http://bigdata.baidu.cn/wangwu
http://javaee.baidu.cn/xiaoxu
http://javaee.baidu.cn/xiaoxu
http://javaee.baidu.cn/laoyang
http://javaee.baidu.cn/laoyang
http://javaee.baidu.cn/laoyang
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/wangwu
http://bigdata.baidu.cn/wangwu
http://javaee.baidu.cn/xiaoxu
http://javaee.baidu.cn/xiaoxu
http://javaee.baidu.cn/laoyang
http://javaee.baidu.cn/laoyang
http://javaee.baidu.cn/laoyang
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/lisi
http://bigdata.baidu.cn/wangwu
http://bigdata.baidu.cn/wangwu
http://javaee.baidu.cn/xiaoxu
http://javaee.baidu.cn/xiaoxu
http://javaee.baidu.cn/laoyang
http://javaee.baidu.cn/laoyang
http://javaee.baidu.cn/laoyang
http://php.baidu.cn/laoli
http://php.baidu.cn/laoliu
http://php.baidu.cn/laoli
http://php.baidu.cn/laoli

全局topn  组内topn

代码：

package dayo1
 
import java.net.URL
 
import org.apache.spark.rdd.RDD
import org.apache.spark.{SparkConf, SparkContext}
 
object teacher2 {
  def main(args: Array[String]): Unit = {
    val conf = new SparkConf ()
      .setAppName ( this.getClass.getSimpleName )
      .setMaster ( "local[1]" )
 
    val sc = new SparkContext ( conf )
 
    val lines = sc.textFile ( "E:\\teacher.log" )
 
    val overAll: RDD[((String, String), Int)] = lines.map ( tp => {
      val teacher: String = tp.split ( "/" ).last
      val host = new URL ( tp ).getHost
      val subject = host.substring ( , host.indexOf ( "." ) )
      ((teacher, subject), )
    } )
    //所有科目和老师的前三
    val topOverAll = overAll.reduceByKey ( _ + _ ).sortBy ( -_._2 ).take (  ).foreach ( println )
 
    //每个科目前两名的老师
    val topGroup = overAll.reduceByKey ( _ + _ ).groupBy ( _._1._2 ).mapValues ( _.toList.sortBy ( -_._2 ).take (  ) ).foreach ( println )
    sc.stop ()
 
  }
}

实例二：

去重

file1:
-- a
-- b
-- c
-- d
-- a
-- b
-- c
-- c
 
file2:
-- b
-- a
-- b
-- d
-- a
-- c
-- d
-- c

代码：

package dayo1
 
import org.apache.spark.{SparkConf, SparkContext}
 
object distinct {
  def main(args: Array[String]): Unit = {
    val cof = new SparkConf ()
      .setAppName ( this.getClass.getSimpleName )
      .setMaster ( "local[1]" )
 
    val sc = new SparkContext ( cof )
 
    val file1 = sc.textFile ( "E:\\file1.txt" )
    val file2 = sc.textFile ( "E:\\file2.txt" )
    val list = file1.union ( file2 ).distinct ().sortBy ( tp => tp )
    list.foreach ( println )
    sc.stop ()
  }
}

实例三：

temperature.txt

0067011990999991950051507004888888889999999N9++
0067011990999991950051512004888888889999999N9++
0067011990999991950051518004888888889999999N9-+
0067011990999991949032412004888888889999999N9++
0067011990999991950032418004888888880500001N9++
0067011990999991950051507004888888880500001N9++

需求：分析每年的最高温度

代码：

package dayo1
 
import org.apache.spark.{SparkConf, SparkContext}
 
/**
  * 0067011990999991950051507004888888889999999N9+00001+9999999999999999999999
  * 0067011990999991950051512004888888889999999N9+00221+9999999999999999999999
  * 0067011990999991950051518004888888889999999N9-00111+9999999999999999999999
  * 0067011990999991949032412004888888889999999N9+01111+9999999999999999999999
  * 0067011990999991950032418004888888880500001N9+00001+9999999999999999999999
  * 0067011990999991950051507004888888880500001N9+00781+9999999999999999999999
  *
  * 12345678911234567892123456789312345678941234567895123456789612345678971234
  * 需求：分析每年的最高温度
  * 数据说明：
  *
  *
  * 第15-19个字符是year 6-9
  *
  * 第45-50位是温度表示，+表示零上 -表示零下，且温度的值不能是9999，9999表示异常数据
  *
  * 第50位值只能是0、1、4、5、9几个数字
  */
object temperature {
  def main(args: Array[String]): Unit = {
    val cof = new SparkConf ()
      .setAppName ( this.getClass.getSimpleName )
      .setMaster ( "local[*]" )
    val sc = new SparkContext ( cof )
 
    val lines = sc.textFile ( "E:\\temperature.txt" )
 
    val yearAndTemp = lines.filter ( tp => {
      var temp =
      val query = tp.charAt (  ).toString //val query=tp.subString(50,51)
      if (tp.charAt (  ).equals ( "+" )) {
        temp = tp.substring ( ,  ).toInt
      } else {
        temp = tp.substring ( ,  ).toInt
      }
      temp !=  && query.matches ( "[01459]" )
 
    } ).map ( tp => {
 
      val year = tp.substring ( ,  )
      var temp =
      if (tp.charAt (  ).equals ( "+" )) {
        temp = tp.substring ( ,  ).toInt
      } else {
        temp = tp.substring ( ,  ).toInt
      }
 
      (year, temp)
    } )
 
    val res = yearAndTemp.reduceByKey ( (x, y) => if (x > y) x else y )
 
    res.foreach ( tp => println ( "year:" + tp._1 + "  temp:" + tp._2 ) )
    sc.stop ()
  }
}