我对溪流的世界还很陌生,我在第一次尝试时就面临着一些问题。
我想做的是在 window: WindowdStream
在下面。我试图实现我自己的功能,但不知道它实际上是如何工作的。
好像什么都没印出来
你有什么提示吗?
val parsedStream: DataStream[(String, Response)] = stream
.mapWith(_.decodeOption[Response])
.filter(_.isDefined)
.map { record =>
(
s"${record.get.group.group_country}, ${record.get.group.group_city}",
record.get
)
}
val topLocations = parsedStream
.keyBy(_._1)
.timeWindow(Time.days(7))
.process(new SortByCountFunction)
排序计数函数
class SortByCountFunction
extends ProcessWindowFunction[(String, Response), MeetUpLocationWindow, String, TimeWindow] {
override def process(key: String,
context: Context,
elements: Iterable[(String, Response)],
out: Collector[MeetUpLocationWindow]): Unit = {
val count: Map[String, Iterable[(String, Response)]] = elements.groupBy(_._1)
val locAndCount: Seq[MeetUpLocation] = count.toList.map(tmp => {
val location: String = tmp._1
val meetUpList: Iterable[(String, Response)] = tmp._2
MeetUpLocation(location, tmp._2.size, meetUpList.map(_._2).toList)
})
val output: List[MeetUpLocation] = locAndCount.sortBy(tup => tup.count).take(20).toList
val windowEnd = context.window.getEnd
out.collect(MeetUpLocationWindow(windowEnd, output))
}
}
case class MeetUpLocationWindow(endTs: Long, locations: List[MeetUpLocation])
case class MeetUpLocation(location: String, count: Int, meetUps: List[Response])
1条答案
按热度按时间epfja78i1#
当flink datastream作业无法生成任何输出时,通常的怀疑是:
作业不会在streamexecutionenvironment上调用execute()(例如。,
env.execute()
)作业没有连接Flume(例如。,
TopLocations.print()
)该作业旨在使用事件时间,但水印设置不正确,或者空闲源阻止水印前进
作业正在写入taskmanager日志,但没有人注意到
输出类型的序列化程序不生成输出
如果没有更多的信息,就很难猜测这些问题中的哪一个可能是本例中的问题。