我正在努力反序列化的avro序列化数据来自Kafka在Spark流。
这是我正在运行的文件spark submit：

package com.example.mymessage

import org.apache.avro.Schema
import org.apache.avro.generic.{GenericDatumReader, GenericRecord}
import org.apache.avro.io.DecoderFactory
import org.apache.log4j.{Level, Logger}
import org.apache.spark.{Logging, SparkConf}
import org.apache.spark.streaming._
import org.apache.spark.streaming.kafka._

object MyMessageCount extends Logging {
  def main(args: Array[String]) {
    if (args.length < 4) {
      System.err.println("Usage: MyMessageCount <zkQuorum> <group> <topics> <numThreads>")
      System.exit(1)
    }

    val log4jInitialized = Logger.getRootLogger.getAllAppenders.hasMoreElements
    if (!log4jInitialized) {
      logInfo("Setting log level to [WARN]." +
        " To override add a custom log4j.properties to the classpath.")
      Logger.getRootLogger.setLevel(Level.WARN)
    }

    val Array(zkQuorum, group, topics, numThreads) = args
    val sparkConf = new SparkConf().setMaster("local[4]").setAppName("MyMessageCount")
    val ssc = new StreamingContext(sparkConf, Seconds(2))
    ssc.checkpoint("checkpoint")

    val topicMap = topics.split(",").map((_, numThreads.toInt)).toMap
    val lines = KafkaUtils.createStream(ssc, zkQuorum, group, topicMap).map(_._2)

    lines.foreachRDD(rdd => {
      rdd.foreach(avroRecord => {
        val schemaString = "{\"type\":\"record\",\"name\":\"myrecord\",\"fields\":[{\"name\":\"string\",\"type\":\"string\"},{\"name\":\"long\",\"type\":\"long\"}]}"
        val parser = new Schema.Parser()
        val schema = parser.parse(schemaString)
        val reader = new GenericDatumReader[GenericRecord](schema)

        val decoder = DecoderFactory.get.binaryDecoder(avroRecord.toCharArray.map(_.toByte), null)
        val record: GenericRecord = reader.read(null, decoder)

        System.out.println(avroRecord + "," + record.toString 
          + ", string= " + record.get("string")
          + ", long=" + record.get("long"))
      })
    })

    ssc.start()
    ssc.awaitTermination()
  }
}

我一直在使用confluent平台在本地发送数据。
如果我发送：

{"string":"test","long":30}

然后上述代码输出：

test<,{"string": "", "long": 0}, string= , long=0

这向我表明数据正在通过，但出于某种原因，字符串和长值显示为类似于默认值的值。如何访问进入的真正的“string”和“long”值 avroRecord 来自Kafka？