我有我的星火流应用程序下面的行编译罚款:为什么Scala编译器会因“无法解析带有这种签名的引用reduceByKeyAndWindow”而失败?
val kafkaDirectStream: InputDStream[ConsumerRecord[String,String]] = KafkaUtils.createDirectStream(...)
kafkaDirectStream.map(_ => ("mockkey", 1)).reduceByKeyAndWindow(_+_, Seconds(30))
当我使用的reduceByKeyAndWindow
变异有两个Duration
S作为如下:
.reduceByKeyAndWindow(_ + _, Seconds(30), Seconds(10))
我面对的下方编译器错误:
Cannot resolve reference reduceByKeyAndWindow with such signature
为什么?