1.算子类型简介

 

 

 

2.map

 

示例：

import org.apache.flink.streaming.api.scala.StreamExecutionEnvironment
import org.apache.flink.streaming.api.scala._

object mapTest {
  def main(args: Array[String]): Unit = {

    //create env
    val env = StreamExecutionEnvironment.getExecutionEnvironment

    //create the data source
    val ds = env.fromElements(1, 2, 3, 4, 5)

    val newDs = ds.map(x => x + 10)
    
    newDs.print()

    env.execute("map test")




  }

}

执行结果：

 

3.自定义map

 

核心操作：

1.创建自定义map类，继承 RichMapFunction 类

2.重写RichMapFunction 类的 map 方法，编辑 in 的处理逻辑

 示例：

import org.apache.flink.api.common.functions.RichMapFunction
import org.apache.flink.api.scala.createTypeInformation
import org.apache.flink.streaming.api.scala.StreamExecutionEnvironment

object myMapTest {




  //override map func
  class MyMapFunc extends RichMapFunction[Int,String]{
    override def map(in: Int): String = {
      "Input: "+in.toString+", OutPut:"+(in*3).toString
      }
    }

  def main(args: Array[String]): Unit = {

    //create env
    val env = StreamExecutionEnvironment.getExecutionEnvironment

    //create dataSource
    val ds = env.fromElements(1, 2, 3, 4, 5)
    
    //use myMap func to transformation
    val newDs = ds.map(new MyMapFunc)

    //pirnt
    newDs.print()

    //execute
    env.execute()


  }

}

输出结果：