代码:

package com.kpwong.sideoutput

import com.atguigu.window.{SensorReading}
import org.apache.flink.streaming.api.functions.ProcessFunction
//import org.apache.flink.streaming.api.functions.timestamps.BoundedOutOfOrdernessTimestampExtractor
import org.apache.flink.streaming.api.scala.{DataStream, StreamExecutionEnvironment}
import org.apache.flink.streaming.api.scala._
//import org.apache.flink.streaming.api.windowing.time.Time
import org.apache.flink.util.Collector

object SideOutPutTest {
  def main(args: Array[String]): Unit = {
    val env: StreamExecutionEnvironment = StreamExecutionEnvironment.getExecutionEnvironment

    val SocketDS: DataStream[String] = env.socketTextStream("hadoop202",9999)

    val sensorStream: DataStream[SensorReading] = SocketDS.map(data => {
      val dataArray: Array[String] = data.split(",")
      SensorReading(dataArray(0).trim, dataArray(1).trim.toLong, dataArray(2).trim.toDouble)
    }).process(new FreeAlert())
//    val processDS: DataStream[SensorReading] = sensorStream.assignTimestampsAndWatermarks(new BoundedOutOfOrdernessTimestampExtractor[SensorReading](Time.seconds(1)) {
//      override def extractTimestamp(element: SensorReading) = {
//        element.timestamp * 1000
//      }
//    }).process(new FreeAlert())

    sensorStream.print("main process flow")

    sensorStream.getSideOutput(new OutputTag[SensorReading]("zeroAlert")).print("Side out put flow")


    env.execute()
  }
}

//冰点报警，如果小于0度，就输出到侧数据流
class FreeAlert extends  ProcessFunction[SensorReading,SensorReading]{
  lazy  val alertOutPut:OutputTag[SensorReading] = new OutputTag[SensorReading]("zeroAlert")
  override def processElement(value: SensorReading, ctx: ProcessFunction[SensorReading, SensorReading]#Context, out: Collector[SensorReading]): Unit = {
    if(value.temperature  < 0.0)
      {
        //小于零度，到侧输出流
        ctx.output(alertOutPut,value)
      }
    else
      {
        out.collect(value)  //主输出流
      }
  }
}