如何在Scala中使用Flink的KafkaSource？

我正在尝试使用 Flink 的 KafkaSource 运行一个简单的测试程序。我正在使用以下内容：

• 弗林克0.9
• 斯卡拉2.10.4
• 卡夫卡0.8.2.1

我按照文档测试 KafkaSource（添加依赖项，将 Kafka 连接器 flink-connector-kafka 捆绑在插件中），如下所述here and here.

下面是我的简单测试程序：

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

object TestKafka {
  def main(args: Array[String]) {
    val env = StreamExecutionEnvironment.getExecutionEnvironment
    val stream = env
     .addSource(new KafkaSource[String]("localhost:2181", "test", new SimpleStringSchema))
     .print
  }
}

然而，编译总是抱怨找不到 KafkaSource：

[ERROR] TestKafka.scala:8: error: not found: type KafkaSource
[ERROR]     .addSource(new KafkaSource[String]("localhost:2181", "test", new SimpleStringSchema))

我在这里想念什么？

我是 sbt 用户所以我使用了以下内容build.sbt:

organization := "pl.japila.kafka"
scalaVersion := "2.11.7"

libraryDependencies += "org.apache.flink" % "flink-connector-kafka" % "0.9.0" exclude("org.apache.kafka", "kafka_${scala.binary.version}")
libraryDependencies += "org.apache.kafka" %% "kafka" % "0.8.2.1"

这让我可以运行该程序：

import org.apache.flink.streaming.api.environment._
import org.apache.flink.streaming.connectors.kafka
import org.apache.flink.streaming.connectors.kafka.api._
import org.apache.flink.streaming.util.serialization._

object TestKafka {
  def main(args: Array[String]) {
    val env = StreamExecutionEnvironment.getExecutionEnvironment
    val stream = env
     .addSource(new KafkaSource[String]("localhost:2181", "test", new SimpleStringSchema))
     .print
  }
}

输出：

[kafka-flink]> run
[info] Running TestKafka
log4j:WARN No appenders could be found for logger (org.apache.flink.streaming.api.graph.StreamGraph).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.
[success] Total time: 0 s, completed Jul 15, 2015 9:29:31 AM