语法是: combineByKey[C](   createCombiner: V => C,   mergeValue: (C, V) => C,   mergeCombiners: (C, C) => C )  标记一下:(因为有很多同样的字母,方便说明我就按照字母+数字标记一下) 语法说明:(不复制网上的,我按照我的理解大白话说明) 1,combineByKey 中的byKey 就是按照键来处理,你就默认 他丫知道 哪些键是一样的,他会在每个分区自动归类同样的键,你就操心怎么处理值

spark用的是cdh spark-2.0.1 package main.scala import org.apache.spark.rdd.RDD import org.apache.spark.{SparkConf, SparkContext} /* Created by tomtang on 2016/12/16. */ object tomhelloworld { def FILE_NAME:String = "word_count_results_" def main(arg

各种报错信息如下: java.lang.NoClassDefFoundError: scala/Function0 at java.lang.Class.getDeclaredMethods0(Native Method) at java.lang.Class.privateGetDeclaredMethods(Class.java:2701) at java.lang.Class.privateGetMethodRecursive(Class.java:3048) at java.lang.C

可以打包的pom.xml: <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">

运行spark官方的graphx 示例 ComprehensiveExample.scala报错解决 在Idea中,直接运行ComprehensiveExample.scala,报需要指定master异常. 修改源码:指定master为local模式, val spark = SparkSession .builder .appName(s"${this.getClass.getSimpleName}").master("local[2]") .getOrCreat

FROM: http://j-q-j.org/scala/scala-2-11-application-error.html 这两天学习scala,官网下载的最新版本2.11,书用的是<Programming in scala>,看到类和对象,这一章最后一段代码 1 2 3 4 5 import ChecksumAccumulator.calculate object FallWinterSpringSummer extends Application {   for (season <

遇到比较奇怪的问题,mvn项目中的main函数可以正常运行,但是test阶段出错,报错信息如下: Exception in thread "main" java.lang.NoClassDefFoundError: scala/ScalaObject at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(Unknown Source) at java.l

代码: 报错信息: java.lang.NoClassDefFoundError: scala/xml/MetaData 原因:确失jar包 <dependency> <groupId>org.scala-lang</groupId> <artifactId>scala-xml</artifactId> <version>2.11.0-M4</version></dependency>

scala的trait执行报错: 错误: 找不到或无法加载主类 cn.itcast.scala.`trait`.Children 原因:包名写成了trait,与trait关键字重名了: package cn.itcast.scala.`trait` 解决方法:将包名trait修改为其他名字,比如trait_demo

一.情况描述 使用idea +scala+spark,运行程序代码如下: package cn.idcast.hello import org.apache.spark.rdd.RDD import org.apache.spark import org.apache.spark.SparkConf import org.apache.spark.SparkContext /** * Author itcast * Desc 演示Spark入门案例-WordCount */ object Wor

如果小于Int.max时他不会报错 def sumcount(str:String): Int ={ val ints = for(c <- str)yield { println(c.asInstanceOf[Int]) ; c.asInstanceOf[Int]} println(ints.reduce(_*_)) println(Int.MaxValue) ints.sum } sumcount("Hello") 721011081081118251528962147483

环境: openSUSE42.2 hadoop2.6.0-cdh5.10.0 spark1.6.0-cdh5.10.0 按照网上的spark安装教程安装完之后,启动spark-shell,出现如下报错: 报错信息: Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/hadoop/fs/FSDataInputStream at org.apache.spark.deploy.SparkSubmitA

1. 使用127.0.0.1启动生产和消费进程: 1)启动生产者进程: bin/kafka-console-producer.sh --broker-list 127.0.0.1:9092 --topic test 输入消息: this is msg 生产者进程报错: [2016-06-03 11:33:47,934] WARN Bootstrap broker 127.0.0.1:9092 disconnected (org.apache.kafka.clients.NetworkClient

spark 2.1.1 一 问题重现 问题代码示例 object MethodPositionTest { val sparkConf = new SparkConf().setAppName("MethodPositionTest") val sc = new SparkContext(sparkConf) val spark = SparkSession.builder().enableHiveSupport().getOrCreate() def main(args : Arra

spark 2.1.1 一 问题重现 spark-submit --master local[*] --class app.package.AppClass --jars /jarpath/zkclient-0.3.jar --driver-memory 1g app.jar 报错 Java HotSpot(TM) 64-Bit Server VM warning: Setting CompressedClassSpaceSize has no effect when compressed cl

kafka0.8.1 一 问题 10月22号应用系统忽然报错: [2014/12/22 11:52:32.738]java.net.SocketException: 打开的文件过多 [2014/12/22 11:52:32.738]       at java.net.Socket.createImpl(Socket.java:447) [2014/12/22 11:52:32.738]       at java.net.Socket.connect(Socket.java:577) [201

最近用yarn cluster方式提交spark任务时,有时会报错,报错几率是40%,报错如下: 18/03/15 21:50:36 116 ERROR ApplicationMaster91: User class threw exception: org.apache.spark.sql.AnalysisException: java.lang.NoSuchFieldError: HIVE_MOVE_FILES_THREAD_COUNT; org.apache.spark.sql.Analy

spark版本:1.6.1 scala版本:2.10 问题呢场景: 在idea调试本地程序的时候创建hiveContext报错,上午的时候是没有这个问题的,下午在项目中写了一个小deamon,出现了而这个问题,下面是我的代码: import cn.com.xxx.common.config.SparkConfig import org.apache.spark.sql.hive.HiveContext object test{ def main(args: Array[String]): Uni

先上代码: table = tablexx.select('*).tablexx.groupBy('x).select('x, xx.count ) tableEnvironment // declare the external system to connect to .connect( new Kafka() .version("0.10") .topic("test-input") .startFromEarliest() .property("z

报错信息: WARN Fetching topic metadata with correlation id 14 for topics [Set(test)] from broker [BrokerEndPoint(2,ubuntu,9092)] failed (kafka.client.ClientUtils$) WARN Fetching topic metadata with correlation id ,ubuntu,)] failed (kafka.client.ClientUti

1.执行Spark运行在yarn上的命令报错 spark-shell --master yarn-client,错误如下所示: // :: ERROR SparkContext: Error initializing SparkContext. org.apache.spark.SparkException: Yarn application has already ended! It might have been killed or unable to launch application