我已经使用完整模式在流式数据帧上应用聚合。为了在本地保存数据帧,我实现了foreach接收器。我能够以文本形式保存数据帧。但我需要将它保存为镶木地板格式。如何将完整输出模式下的流聚合保存为实木复合地板?
val writerForText = new ForeachWriter[Row] {
var fileWriter: FileWriter = _
override def process(value: Row): Unit = {
fileWriter.append(value.toSeq.mkString(","))
}
override def close(errorOrNull: Throwable): Unit = {
fileWriter.close()
}
override def open(partitionId: Long, version: Long): Boolean = {
FileUtils.forceMkdir(new File(s"src/test/resources/${partitionId}"))
fileWriter = new FileWriter(new File(s"src/test/resources/${partitionId}/temp"))
true
}
}
val columnName = "col1"
frame.select(count(columnName),count(columnName),min(columnName),mean(columnName),max(columnName),first(columnName), last(columnName), sum(columnName))
.writeStream.outputMode(OutputMode.Complete()).foreach(writerForText).start()
我该如何做到这一点? 在此先感谢!
你找到了一种方法来保存完整/更新模式,以实木复合地板? –
是的,我写了使用https://github.com/chtefi/parquet-custom-reader-writer –