scala – 结构化流 – Foreach接收器

如果这实际上有效,我将在这里实际执行流程方法中的一些业务逻辑,但是,这不起作用.我相信println因为在执行程序上运行而无法工作,并且无法将这些日志恢复到驱动程序.但是,这个插入临时表应该至少可以工作,并告诉我消息实际上被消耗并处理到接收器.

我在这里错过了什么？

真的在寻找第二组眼睛来检查我的努力：

val stream = spark
      .readStream
      .format("kafka")
      .option("kafka.bootstrap.servers",Util.getProperty("kafka10.broker")) 
      .option("subscribe",src_topic) 
      .load()

    val rec = stream.selectExpr("CAST(value AS STRING) as txnJson").as[(String)]

    val df = stream.selectExpr("cast (value as string) as json")

    val writer = new ForeachWriter[Row] {
      val scon = new SConConnection
      override def open(partitionId: Long,version: Long) = {
        true
      }
      override def process(value: Row) = {
        println("++++++++++++++++++++++++++++++++++++" + value.get(0))
        scon.executeUpdate("insert into rs_kafka10(miscCol) values("+value.get(0)+")")
      }
      override def close(errorOrNull: Throwable) = {
        scon.closeConnection
      }
    }


    val yy = df.writeStream
      .queryName("ForEachQuery")
      .foreach(writer)
      .outputMode("append")
      .start()

    yy.awaitTermination()