Flink--Window apply

和window的操作类似，只不过操作更加灵活，具体的操作需要在匿名内部类的方法中实现；当有比较复杂的需求时候，可以使用；

object WindowApply {
  def main(args: Array[String]): Unit = {
    val env = StreamExecutionEnvironment.getExecutionEnvironment
    val textStream: DataStream[String] = env.socketTextStream("localhost" , 9999)
    val flatmapdata: DataStream[String] = textStream.flatMap(x => x.split(","))
    val mapdata: DataStream[(String, Int)] = flatmapdata.map(line => (line,1))
    val keybyStream: KeyedStream[(String, Int), String] = mapdata.keyBy(line => line._1)
    val window: WindowedStream[(String, Int), String, TimeWindow] = keybyStream.timeWindow(Time.of(1 , TimeUnit.SECONDS) ,Time.of(100,TimeUnit.MILLISECONDS))
    val data = window.apply(new WindowFunction[(String, Int) , (String, Int) , String , TimeWindow] {
      override def apply(key: String,
                         window: TimeWindow,
                         input: Iterable[(String, Int)],
                         out: Collector[(String, Int)]): Unit = {
        var output = ""
        var index = 0
        for(in <- input){
            output += "key :" + in._1 + "   value:"+in._2
            index = index + 1
          out.collect(output , index)
          }
      }
    })
    data.print()
    env.execute()

  }
}

注意，例子中使用的是window，所以对应的匿名内部类是：WindowFunction

如果使用的是windowAll，则需要使用的内部类是：AllWindowFunction