SparkStreaming中的转换算子1

转换算子1---map,flatMap

• RDD支持的转换算子DStream大部分都是支持的
  map、flatMap、filter、distinct、union、join、reduceByKey......
  RDD中部分行动算子DStream会当作转换算子使用，算子的执行逻辑是一样的

package SparkStreaming.trans

import org.apache.spark.SparkConf
import org.apache.spark.storage.StorageLevel
import org.apache.spark.streaming.dstream.DStream
import org.apache.spark.streaming.{Milliseconds, StreamingContext}

object Transform1 {
  def main(args: Array[String]): Unit = {
    val conf = new SparkConf().setAppName("trans1").setMaster("local[3]")
    val ssc = new StreamingContext(conf, Milliseconds(5000))
    val ds = ssc.socketTextStream("node1", 44444, StorageLevel.MEMORY_ONLY_SER)
    /**
     * 将用户通过端口发送的 脏话过滤
     */
    //1、脏话使用*来表示
    val ds1 = ds.map((line: String) => {
      val str = line.replaceAll("操", "*").replaceAll("草", "*")
      str
    })
    // 2. 脏话直接不显示  直接过滤掉
    val ds2 = ds.filter((line: String) => {
      if (line.contains("屮") || line.contains("尼玛")) {
        false
      } else {
        true
      }
    })
    println("-------")
    ds1.print()
    println("-------")
    ds2.print()
    println("-------")

    ssc.start()
    ssc.awaitTermination()
  }
}

转换算子2 count reduce

package SparkStreaming.trans

import org.apache.spark.SparkConf
import org.apache.spark.storage.StorageLevel
import org.apache.spark.streaming.dstream.DStream
import org.apache.spark.streaming.{Milliseconds, StreamingContext}
/**
 *  DStream中reduce、count两个算子  在我们的RDD中属于行动算子，但是在DStream中是转换算子
 *  两个算子会给我们返回一个新的DStream，DStream就是reduce和count计算完成的结果类型
 */
object Transform2 {
  def main(args: Array[String]): Unit = {
    val conf = new SparkConf().setAppName("trans2").setMaster("local[2]")
    val ssc = new StreamingContext(conf, Milliseconds(3000))

    val ds = ssc.socketTextStream("node1", 44444, StorageLevel.MEMORY_ONLY)
    val ds1: DStream[Long] = ds.count()
    val ds2 = ds.reduce(_ + _)
    ds1.print()
    ds2.print()

    ssc.start()
    ssc.awaitTermination()
  }
}

转换算子3 transform

• DStream中一个特殊转换算子transform

package SparkStreaming.trans

import org.apache.spark.SparkConf
import org.apache.spark.SparkContext
import org.apache.spark.rdd.RDD
import org.apache.spark.storage.StorageLevel
import org.apache.spark.streaming.dstream.DStream
import org.apache.spark.streaming.{Seconds, StreamingContext}

object Transform3 {
  def main(args: Array[String]): Unit = {
    val conf = new SparkConf().setMaster("local[3]").setAppName("transform3")
    val ssc = new StreamingContext(conf, Seconds(3))
    val ds = ssc.socketTextStream("node1", 44444, StorageLevel.MEMORY_ONLY)
    val ds1:DStream[(String,Int)] = ds.flatMap(_.split(" ")).map((_, 1)).reduceByKey(_ + _)
    val ds3 = ds.transform((rdd: RDD[String]) => {
      val ds2: RDD[(String, Int)] = rdd.flatMap(_.split(" ")).map((_, 1)).reduceByKey(_ + _)
      ds2
    })
    ds1.print()
    ds3.print()

    ssc.start()
    ssc.awaitTermination()
  }
}