spark-streaming-kafka怎样通过KafkaUtils.createDirectStream的方式处理数据

spark-streaming-kafka怎样通过KafkaUtils.createDirectStream的方式处理数据，相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。

package hgs.spark.streamingimport org.apache.spark.SparkConfimport org.apache.spark.SparkContextimport org.apache.spark.streaming.StreaminGContextimport org.apache.spark.streaming.Secondsimport org.apache.spark.streaming.kafka.KafkaUtilsimport org.apache.spark.streaming.kafka.KafkaClusterimport Scala.collection.immutable.Mapimport java.util.NoSuchElementExceptionimport org.apache.spark.SparkExceptionimport kafka.common.TopicAndPartitionimport kafka.message.MessageAndMetadataimport org.codehaus.jackson.map.deser.std.PrimitiveArrayDeserializers.StringDeserimport kafka.serializer.StringDecoderimport org.apache.spark.streaming.kafka.DirectKafkaInputDStreamimport org.apache.spark.rdd.RDDimport org.apache.spark.streaming.kafka.HasOffsetRangesimport org.apache.spark.HashPartitionerobject SparkStreamingKafkaDirectWordCount {  def main(args: Array[String]): Unit = {     val conf = new SparkConf().setAppName("KafkaWordCount").setMaster("local[5]")     conf.set("spark.streaming.kafka.maxRatePerPartition", "1")     val sc = new SparkContext(conf)     val ssc = new StreamingContext(sc,Seconds(1))      ssc.checkpoint("d:\\checkpoint")     val kafkaParams = Map[String,String](         "metadata.broker.list"->"bigdata01:9092,bigdata02:9092,bigdata03:9092",         "group.id"->"group_hgs",         "ZooKeeper.connect"->"bigdata01:2181,bigdata02:2181,bigdata03:2181")     val kc = new KafkaCluster(kafkaParams)     val topics = Set[String]("test")     //每个rdd返回的数据是(K,V)类型的，该函数规定了函数返回数据的类型     val mmdFunct = (mmd: MessageAndMetadata[String, String])=>(mmd.topic+" "+mmd.partition,mmd.message())          val rds = KafkaUtils.createDirectStream[String,String,StringDecoder,StringDecoder,(String,String)](ssc, kafkaParams, getOffsets(topics,kc,kafkaParams),mmdFunct)     val updateFunc=(iter:Iterator[(String,Seq[Int],Option[Int])])=>{        //iter.flatMap(it=>Some(it._2.sum+it._3.getOrElse(0)).map((it._1,_)))//方式一        //iter.flatMap{case(x,y,z)=>{Some(y.sum+z.getOrElse(0)).map((x,_))}}//方式二        iter.flatMap(it=>Some(it._1,(it._2.sum.toInt+it._3.getOrElse(0))))//方式三      }     val words = rds.flatMap(x=>x._2.split(" ")).map((_,1))     //val wordscount = words.map((_,1)).updateStateByKey(updateFunc, new HashPartitioner(sc.defaultMinPartitions), true)     //println(getOffsets(topics,kc,kafkaParams))     rds.foreachRDD(rdd=>{       if(!rdd.isEmpty()){         //对每个dataStreamoffset进行更新         upateOffsets(topics,kc,rdd,kafkaParams)       }     }       )          words.print()     ssc.start()     ssc.awaitTermination()           }        def getOffsets(topics : Set[String],kc:KafkaCluster,kafkaParams:Map[String,String]):Map[TopicAndPartition, Long]={       val topicAndPartitionsOrNull =  kc.getPartitions(topics)    if(topicAndPartitionsOrNull.isLeft){      throw new SparkException(s"$topics in the set may not found")    }    else{      val topicAndPartitions = topicAndPartitionsOrNull.right.get      val groups = kafkaParams.get("group.id").get      val offsetOrNull = kc.getConsumerOffsets(groups, topicAndPartitions)      if(offsetOrNull.isLeft){        println(s"$groups you assignment may not exists!now redirect to zero!")        //如果没有消费过，则从最开始的位置消费        val erliestOffset = kc.getEarliestLeaderOffsets(topicAndPartitions)        if(erliestOffset.isLeft)          throw new SparkException(s"Topics and Partions not definded not found!")        else          erliestOffset.right.get.map(x=>(x._1,x._2.offset))      }      else{        //如果消费组已经存在则从记录的地方开始消费        offsetOrNull.right.get      }    }      }    //每次拉取数据后存储offset到ZK  def upateOffsets(topics : Set[String],kc:KafkaCluster,directRDD:RDD[(String,String)],kafkaParams:Map[String,String]){    val offsetRanges =  directRDD.asInstanceOf[HasOffsetRanges].offsetRanges    for(offr <-offsetRanges){      val topicAndPartitions = TopicAndPartition(offr.topic,offr.partition)      val yesOrNo = kc.setConsumerOffsets(kafkaParams.get("group.id").get, Map(topicAndPartitions->offr.untilOffset))      if(yesOrNo.isLeft){        println(s"Error when update offset of $topicAndPartitions")      }    }  }     }

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