Kafka Producer:

{"createTime":"1532598069","event":{"info":{"AAA":"three","BBB":"four","CCC":"haha"}}}

Kafka Consumer:

import org.apache.spark.sql.SparkSession
import org.apache.spark.sql.functions._
import org.apache.spark.sql.streaming._
import org.apache.spark.sql.types._


object  extends App {
  val spark 
 
= SparkSession
    .builder
    .appName("DynamicSchema")
    .master("local[*]")
    .getOrCreate()

  
  val schema = new StructType()
    .add("createTime", StringType)
    .add("event", MapType(StringType, new StructType()
      .add("AAA", StringType, true)
      .add("BBB", StringType, true)
      .add(
 
"CCC", StringType, true)
      .add("DDD", StringType, true)
    ))

  val parsed = spark.readStream
    .format("kafka")
    .option("kafka.bootstrap.servers", "localhost:9092")
    .option("subscribe", "dynamic-schema")
    .option("startingOffsets", "earliest")
    .load()
    .select(from_json(col("
 
value").cast("string"), schema).alias("parsed_value"))

  import spark.implicits._

  val event = parsed.select(explode($"parsed_value.event")).select("value.*")

  val console = event.writeStream
    .format("console")
    .outputMode(OutputMode.Append())

  val query = console.start()

  query.awaitTermination()

}

StructuredStreaming輸出結果:

+-----+----+----+----+
|  AAA| BBB| CCC| DDD|
+-----+----+----+----+
|three|four|haha|null|
+-----+----+----+----+

連結:https://www.dazhuanlan.com/2019/11/20/5dd51853cd505/