Kafka上的Spark Streaming为kafka的不同值打印不同的大小写

import org.apache.spark.streaming.kafka010._
import org.apache.kafka.common.serialization.StringDeserializer

val kafkaParams = Map[String, Object](
  "bootstrap.servers" -> "kafka_server:9092",
  "key.deserializer" -> classOf[StringDeserializer],
  "value.deserializer" -> classOf[StringDeserializer],
  "group.id" -> "spark-streaming",
  "auto.offset.reset" -> "latest",
  "enable.auto.commit" -> (false: java.lang.Boolean)
)

val topics = Array("kafka_topic")
val stream = KafkaUtils.createDirectStream[String, String](
  streamingContext,
  PreferConsistent,
  Subscribe[String, String](topics, kafkaParams)
)

stream.map(record => {
  val key = record.key()
  val value = record.value()
  
  // 根据不同值进行大小写转换并打印
  val transformedValue = if (value == "lowercase") value.toLowerCase else value.toUpperCase
  println(transformedValue)
})