【问题标题】:"No implicits found" when creating a Flink DataStream from a collection of Case Classes从案例类集合创建 Flink DataStream 时“未找到隐含”
【发布时间】:2019-07-19 06:30:20
【问题描述】:

我正在尝试做一个flink scala api hello world,但我无法复制从https://www.slideshare.net/dataArtisans/apache-flink-datastream-api-basics/20 看到的开始教程 sn-p

我尝试的副本是:

  val env = StreamExecutionEnvironment.getExecutionEnvironment
  case class Order(user: String, product: String, amount: Double, proctime: Int, rowtime: Int)

  def basic() = {
    val seq = (1 to 50).map { i => Order(s"User" + (i % 10).toString, "Product" + (i % 20), 2.0 * (4 * i +.5 * i * i -.1 * i * i * i), i * 10, i * 3) }
    val ds: DataStream[Order] = env.fromElements(seq:_*)

然而,隐式不起作用,给

错误:(21, 30) 找不到类型的证据参数的隐式值 org.apache.flink.api.common.typeinfo.TypeInformation[com.blazedb.spark.FlinkDemo.Order]

这里需要改变什么?

【问题讨论】:

    标签: scala apache-flink implicit


    【解决方案1】:

    做事

    import org.apache.flink.streaming.api.scala._
    

    为了导入隐式TypeInformation[T]

    https://github.com/apache/flink/blob/master/flink-scala/src/main/scala/org/apache/flink/api/scala/package.scala#L49

    【讨论】:

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