Maven组件如下：
<dependency>
<groupId>org.apache.spark</groupId>
<artifactId>spark-streaming-kafka-0-10_2.11</artifactId>
<version>2.3.0</version>
</dependency>
官网代码如下：
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// scalastyle:off println
package org.apache.spark.examples.streaming
import org.apache.spark.SparkConf
import org.apache.spark.streaming._
import org.apache.spark.streaming.kafka010._
/**
* Consumes messages from one or more topics in Kafka and does wordcount.
* Usage: DirectKafkaWordCount <brokers> <topics>
* <brokers> is a list of one or more Kafka brokers
* <topics> is a list of one or more kafka topics to consume from
*
* Example:
* $ bin/run-example streaming.DirectKafkaWordCount broker1-host:port,broker2-host:port
* topic1,topic2
*/
object DirectKafkaWordCount {
def main(args: Array[String]) {
if (args.length < 2) {
System.err.println(s"""
|Usage: DirectKafkaWordCount <brokers> <topics>
| <brokers> is a list of one or more Kafka brokers
| <topics> is a list of one or more kafka topics to consume from
|
""".stripMargin)
System.exit(1)
}
StreamingExamples.setStreamingLogLevels()
val Array(brokers, topics) = args
// Create context with 2 second batch interval
val sparkConf = new SparkConf().setAppName("DirectKafkaWordCount")
val ssc = new StreamingContext(sparkConf, Seconds(2))
// Create direct kafka stream with brokers and topics
val topicsSet = topics.split(",").toSet
val kafkaParams = Map[String, String]("metadata.broker.list" -> brokers)
val messages = KafkaUtils.createDirectStream[String, String](
ssc,
LocationStrategies.PreferConsistent,
ConsumerStrategies.Subscribe[String, String](topicsSet, kafkaParams))
// Get the lines, split them into words, count the words and print
val lines = messages.map(_.value)
val words = lines.flatMap(_.split(" "))
val wordCounts = words.map(x => (x, 1L)).reduceByKey(_ + _)
wordCounts.print()
// Start the computation
ssc.start()
ssc.awaitTermination()
}
}
// scalastyle:on println
运行以上代码出现如下错误等：
Exception in thread "main" org.apache.kafka.common.config.ConfigException: Missing required configuration "bootstrap.servers" which has no default value.
由错误可见，是因为没有设置kafka相关参数。
把官网代码修改如下：
package cn.xdf.userprofile.stream
import org.apache.spark.SparkConf
import org.apache.spark.streaming.{Seconds, StreamingContext}
import org.apache.spark.streaming.kafka010._
import scala.collection.mutable
object DirectKafka {
def main(args: Array[String]): Unit = {
if (args.length < 2) {
System.err.println(
s"""
|Usage: DirectKafkaWordCount <brokers> <topics>
| <brokers> is a list of one or more Kafka brokers
| <topics> is a list of one or more kafka topics to consume from
|
""".stripMargin)
System.exit(1)
}
val Array(brokers,topics)=args
var conf = new SparkConf()
.setAppName("DirectKafka")
.setMaster("local[2]")
val ssc = new StreamingContext(conf, Seconds(2))
val topicsSet=topics.split(",").toSet
val kafkaParams=mutable.HashMap[String,String]()
//必须添加以下参数，否则会报错
kafkaParams.put("bootstrap.servers" ,brokers)
kafkaParams.put("group.id", "group1")
kafkaParams.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer")
kafkaParams.put("value.deserializer" , "org.apache.kafka.common.serialization.StringDeserializer")
val messages=KafkaUtils.createDirectStream [String,String](
ssc,
LocationStrategies.PreferConsistent,
ConsumerStrategies.Subscribe[String,String](topicsSet,kafkaParams
)
)
// Get the lines, split them into words, count the words and print
val lines = messages.map(_.value)
val words = lines.flatMap(_.split(" "))
val wordCounts = words.map(x => (x, 1L)).reduceByKey(_ + _)
wordCounts.print()
// Start the computation
ssc.start()
ssc.awaitTermination()
}
}
运行过程如下：
启动kafka
bin/kafka-server-start ./etc/kafka/server.properties &
[2018-10-22 11:24:14,748] INFO [GroupCoordinator 0]: Stabilized group group1 generation 1 (__consumer_offsets-40) (kafka.coordinator.group.GroupCoordinator)
[2018-10-22 11:24:14,761] INFO [GroupCoordinator 0]: Assignment received from leader for group group1 for generation 1 (kafka.coordinator.group.GroupCoordinator)
[2018-10-22 11:24:14,779] INFO Updated PartitionLeaderEpoch. New: {epoch:0, offset:0}, Current: {epoch:-1, offset-1} for Partition: __consumer_offsets-40. Cache now contains 0 entries. (kafka.server.epoch.LeaderEpochFileCache)
[2018-10-22 11:28:19,010] INFO [GroupCoordinator 0]: Preparing to rebalance group group1 with old generation 1 (__consumer_offsets-40) (kafka.coordinator.group.GroupCoordinator)
[2018-10-22 11:28:19,013] INFO [GroupCoordinator 0]: Group group1 with generation 2 is now empty (__consumer_offsets-40) (kafka.coordinator.group.GroupCoordinator)
[2018-10-22 11:29:29,424] INFO [GroupMetadataManager brokerId=0] Removed 0 expired offsets in 11 milliseconds. (kafka.coordinator.group.GroupMetadataManager)
[2018-10-22 11:39:29,414] INFO [GroupMetadataManager brokerId=0] Removed 0 expired offsets in 1 milliseconds. (kafka.coordinator.group.GroupMetadataManager)
[2018-10-22 11:49:29,414] INFO [GroupMetadataManager brokerId=0] Removed 0 expired offsets in 1 milliseconds. (kafka.coordinator.group.GroupMetadataManager)
运行spark
/usr/local/spark-2.3.0/bin/spark-submit --class cn.xdf.userprofile.stream.DirectKafka --master yarn --driver-memory 2g --num-executors 1 --executor-memory 2g --executor-cores 1 userprofile2.0.jar localhost:9092 test
2018-10-22 11:28:16 INFO DAGScheduler:54 - Submitting 1 missing tasks from ResultStage 483 (ShuffledRDD[604] at reduceByKey at DirectKafka.scala:46) (first 15 tasks are for partitions Vector(1))
2018-10-22 11:28:16 INFO TaskSchedulerImpl:54 - Adding task set 483.0 with 1 tasks
2018-10-22 11:28:16 INFO TaskSetManager:54 - Starting task 0.0 in stage 483.0 (TID 362, localhost, executor driver, partition 1, PROCESS_LOCAL, 7649 bytes)
2018-10-22 11:28:16 INFO Executor:54 - Running task 0.0 in stage 483.0 (TID 362)
2018-10-22 11:28:16 INFO ShuffleBlockFetcherIterator:54 - Getting 0 non-empty blocks out of 1 blocks
2018-10-22 11:28:16 INFO ShuffleBlockFetcherIterator:54 - Started 0 remote fetches in 0 ms
2018-10-22 11:28:16 INFO Executor:54 - Finished task 0.0 in stage 483.0 (TID 362). 1091 bytes result sent to driver
2018-10-22 11:28:16 INFO TaskSetManager:54 - Finished task 0.0 in stage 483.0 (TID 362) in 4 ms on localhost (executor driver) (1/1)
2018-10-22 11:28:16 INFO TaskSchedulerImpl:54 - Removed TaskSet 483.0, whose tasks have all completed, from pool
2018-10-22 11:28:16 INFO DAGScheduler:54 - ResultStage 483 (print at DirectKafka.scala:47) finished in 0.008 s
2018-10-22 11:28:16 INFO DAGScheduler:54 - Job 241 finished: print at DirectKafka.scala:47, took 0.009993 s
-------------------------------------------
Time: 1540178896000 ms
-------------------------------------------
启动生产者
[root@master kafka_2.11-1.0.0]# bin/kafka-console-producer.sh --topic test --broker-list localhost:9092
> hello you
> hello me
查看结果：
(hello,2)
(me,1)
(you,1)
2018-10-22 11:57:08 INFO JobScheduler:54 - Finished job streaming job 1540180628000 ms.0 from job set of time 1540180628000 ms
2018-10-22 11:57:08 INFO JobScheduler:54 - Total delay: 0.119 s for time 1540180628000 ms (execution: 0.072 s)
2018-10-22 11:57:08 INFO ShuffledRDD:54 - Removing RDD 154 from persistence list
2018-10-22 11:57:08 INFO MapPartitionsRDD:54 - Removing RDD 153 from persistence list
2018-10-22 11:57:08 INFO BlockManager:54 - Removing RDD 153
2018-10-22 11:57:08 INFO BlockManager:54 - Removing RDD 154
2018-10-22 11:57:08 INFO MapPartitionsRDD:54 - Removing RDD 152 from persistence list
2018-10-22 11:57:08 INFO BlockManager:54 - Removing RDD 152
2018-10-22 11:57:08 INFO MapPartitionsRDD:54 - Removing RDD 151 from persistence list
2018-10-22 11:57:08 INFO BlockManager:54 - Removing RDD 151
2018-10-22 11:57:08 INFO KafkaRDD:54 - Removing RDD 150 from persistence list
2018-10-22 11:57:08 INFO BlockManager:54 - Removing RDD 150