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  • Spark安装

    本文搭建环境为:Mac + Parallel Desktop + CentOS7 + JDK7 + Hadoop2.6 + Scala2.10.4 + IDEA14.0.5


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    一、CentOS安装

    ■ 安装完成后记得保存快照

    ■ 环境准备
      CentOS7下载:http://mirrors.163.com/centos/7/isos/x86_64/CentOS-7-x86_64-DVD-1511.iso

    ■ Mac Parallel Desktop安装CentOS 7 - http://www.linuxidc.com/Linux/2016-08/133827.htm
    配置网卡(无需)
      [root@localhost ~]# vi /etc/sysconfig/network-scripts/ifcfg-eth0
    保存后重启网卡
      /etc/init.d/network stop
      /etc/init.d/network start

    安装网络工具包(无需)
      yum install net-tools
      yum install wget

    packagekit问题:yum安装出现“/var/run/yum.pid 已被锁定,强行解除锁
      rm -f /var/run/yum.pid

    更改源为阿里云
      cd /etc/yum.repos.d/
      mv CentOS-Base.repo Centos-Base.repo.bak
      wget -O CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
      yum clean all
      yum makecache

    ■ CentOS 7 GNOME 图形界面(无需)
      yum groupinstall "X Window System"
      yum groupinstall "GNOME Desktop"
      startx --> 进入图形界面
      runlevel —> 运行级别查看

    ■ CentOS 7安装后配置
      http://www.cnblogs.com/pinnsvin/p/5889857.html
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    二、JDK安装

    CentOS卸载openjdk

      卸载CentOS7-x64自带的OpenJDK并安装Sun的JDK7 - http://www.cnblogs.com/CuteNet/p/3947193.html

      rpm -qa | grep java

      以下命令需根据上一指令结果:

      rpm -e --nodeps python-javapackages-3.4.1-11.el7.noarch
      rpm -e --nodeps java-1.8.0-openjdk-headless-1.8.0.65-3.b17.el7.x86_64
      rpm -e --nodeps java-1.7.0-openjdk-1.7.0.91-2.6.2.3.el7.x86_64
      rpm -e --nodeps java-1.7.0-openjdk-headless-1.7.0.91-2.6.2.3.el7.x86_64
      rpm -e --nodeps tzdata-java-2015g-1.el7.noarchrpm -e --nodeps javapackages-tools-3.4.1-11.el7.noarchrpm -e --nodeps java-1.8.0-openjdk-1.8.0.65-3.b17.el7.x86_64


    CentOS安装Oracle JDK1.7

      http://www.oracle.com/technetwork/java/javase/downloads/jdk7-downloads-1880260.html,下载jdk-7u79-linux-x64.tar.gz

      mkdir /usr/local/java
      cp jdk-7u79-linux-x64.tar.gz /usr/local/java
      cd /usr/local/java
      tar xvf jdk-7u79-linux-x64.tar.gz
      rm jdk-7u79-linux-x64.tar.gz

    设置jdk环境变量

      vim /etc/profile

    打开之后在末尾添加
      export JAVA_HOME=/usr/local/java/jdk1.7.0_79
      export JRE_HOME=/usr/local/java/jdk1.7.0_79/jre
      export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib
      export PATH=$JAVA_HOME/bin:$PATH

    执行配置文件,令其立刻生效
      source /etc/profile

    验证是否安装成功
      java -version
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    三、Hadoop安装

    http://dblab.xmu.edu.cn/blog/install-hadoop-in-centos/

    su
    useradd -m hadoop -s /bin/bash
    passwd hadoop(hadoop)
    visudo
    hadoop ALL=(ALL) ALL

    rpm -qa | grep ssh

    cd ~/.ssh/
    ssh-keygen -t rsa 都按回车
    cat id_rsa.pub >> authorized_keys
    chmod 600 ./authorized_keys

    下载Hadoop:http://mirrors.cnnic.cn/apache/hadoop/common/hadoop-2.6.0/hadoop-2.6.0.tar.gz

    sudo tar -zxf ~/home/hadoop/桌面/hadoop-2.6.0.tar.gz -C /usr/local
    cd /usr/local/
    mv ./hadoop-2.6.0/ ./hadoop
    sudo chown -R hadoop:hadoop ./hadoop

    检查是否可用
    cd /usr/local/hadoop
    ./bin/hadoop version
    Hadoop 2.6.0
    Subversion https://git-wip-us.apache.org/repos/asf/hadoop.git -r e3496499ecb8d220fba99dc5ed4c99c8f9e33bb1
    Compiled by jenkins on 2014-11-13T21:10Z
    Compiled with protoc 2.5.0
    From source with checksum 18e43357c8f927c0695f1e9522859d6a
    This command was run using /usr/local/hadoop/share/hadoop/common/hadoop-common-2.6.0.jar

    --> Hadoop初步环境搭建完成

    Hadoop单机配置(非分布式)

    cd /usr/local/hadoop
    mkdir ./input
    cp ./etc/hadoop/*.xml ./input # 将配置文件作为输入文件
    ./bin/hadoop jar ./share/hadoop/mapreduce/hadoop-mapreduce-examples-*.jar grep ./input ./output 'dfs[a-z.]+'
    cat ./output/* # 查看运行结果

    rm -r ./output

    gedit ~/.bashrc

    export HADOOP_HOME=/usr/local/hadoop
    export HADOOP_INSTALL=$HADOOP_HOME
    export HADOOP_MAPRED_HOME=$HADOOP_HOME
    export HADOOP_COMMON_HOME=$HADOOP_HOME
    export HADOOP_HDFS_HOME=$HADOOP_HOME
    export YARN_HOME=$HADOOP_HOME
    export HADOOP_COMMON_LIB_NATIVE_DIR=$HADOOP_HOME/lib/native
    export PATH=$PATH:$HADOOP_HOME/sbin:$HADOOP_HOME/bin

    export JAVA_HOME=/usr/local/java/jdk1.7.0_79
    export JRE_HOME=/usr/local/java/jdk1.7.0_79/jre
    export CLASSPATH=.:$JAVA_HOME/lib/dt.jar:$JAVA_HOME/lib/tools.jar:$JRE_HOME/lib
    export PATH=$JAVA_HOME/bin:$PATH


    source ~/.bashrc


    gedit ./etc/hadoop/core-site.xml
    <configuration>
    <property>
    <name>hadoop.tmp.dir</name>
    <value>file:/usr/local/hadoop/tmp</value>
    <description>Abase for other temporary directories.</description>
    </property>
    <property>
    <name>fs.defaultFS</name>
    <value>hdfs://localhost:9000</value>
    </property>
    </configuration>


    gedit ./etc/hadoop/hdfs-site.xml
    <configuration>
    <property>
    <name>dfs.replication</name>
    <value>1</value>
    </property>
    <property>
    <name>dfs.namenode.name.dir</name>
    <value>file:/usr/local/hadoop/tmp/dfs/name</value>
    </property>
    <property>
    <name>dfs.datanode.data.dir</name>
    <value>file:/usr/local/hadoop/tmp/dfs/data</value>
    </property>
    </configuration>

    ./bin/hdfs namenode –format

    ./sbin/start-dfs.sh
    显示如下:
    [hadoop@localhost hadoop]$ jps
    27710 NameNode
    28315 SecondaryNameNode
    28683 Jps
    27973 DataNode

    问题

    WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
      tar -x hadoop-native-64-2.6.0.tar -C /usr/local/hadoop/lib/native/
      cp /usr/local/hadoop/lib/native/* /usr/local/hadoop/lib/


    加入系统变量
    export HADOOP_COMMON_LIB_NATIVE_DIR=/home/administrator/work/hadoop-2.6.0/lib/native
    export HADOOP_OPTS="-Djava.library.path=/home/administrator/work/hadoop-2.6.0/lib"
    export HADOOP_ROOT_LOGGER=DEBUG,console

    主要是jre目录下缺少了libhadoop.so和libsnappy.so两个文件。具体是,spark-shell依赖的是scala,scala依赖的是JAVA_HOME下的jdk,libhadoop.so和libsnappy.so两个文件应该放到$JAVA_HOME/jre/lib/amd64下面。
    这两个so:libhadoop.so和libsnappy.so。前一个so可以在HADOOP_HOME下找到,如hadooplib ative。第二个libsnappy.so需要下载一个snappy-1.1.0.tar.gz,然后./configure,make编译出来,编译成功之后在.libs文件夹下。
    当这两个文件准备好后再次启动spark shell不会出现这个问题。
    链接:https://www.zhihu.com/question/23974067/answer/26267153

    问题:由于在root用户下安装Java,而Hadoop用户缺少操作java目录的权限

    cd /
    sudo chown -R hadoop:hadoop ./usr/local/java

    Hadoop开启关闭调试信息

    开启:export HADOOP_ROOT_LOGGER=DEBUG,console
    关闭:export HADOOP_ROOT_LOGGER=INFO,console

    Hadoop伪分布式实例

    ./bin/hdfs dfs -mkdir -p /user/hadoop

    ./bin/hdfs dfs -mkdir input
    ./bin/hdfs dfs -put ./etc/hadoop/*.xml input
    ./bin/hdfs dfs -ls input

    ./bin/hadoop jar ./share/hadoop/mapreduce/hadoop-mapreduce-examples-*.jar grep input output 'dfs[a-z.]+'

    ./bin/hdfs dfs -cat output/*

    rm -r ./output # 先删除本地的 output 文件夹(如果存在)
    ./bin/hdfs dfs -get output ./output # 将 HDFS 上的 output 文件夹拷贝到本机
    cat ./output/*


    Hadoop 运行程序时,输出目录不能存在,否则会提示错误 “org.apache.hadoop.mapred.FileAlreadyExistsException: Output directory hdfs://localhost:9000/user/hadoop/output already exists” ,因此若要再次执行,需要执行如下命令删除 output 文件夹:
    ./bin/hdfs dfs -rm -r output # 删除 output 文件夹

    关闭Hadoop
    ./sbin/stop-dfs.sh

    下次启动 hadoop 时,无需进行 NameNode 的初始化,只需要运行
    ./sbin/start-dfs.sh 就可以!

    启动YARN

    YARN 是从 MapReduce 中分离出来的,负责资源管理与任务调度。YARN 运行于 MapReduce 之上,提供了高可用性、高扩展性,YARN 的更多介绍在此不展开,有兴趣的可查阅相关资料。
    上述通过 ./sbin/start-dfs.sh 启动 Hadoop,仅仅是启动了 MapReduce 环境,我们可以启动 YARN ,让 YARN 来负责资源管理与任务调度。

    ./sbin/start-dfs.sh

    mv ./etc/hadoop/mapred-site.xml.template ./etc/hadoop/mapred-site.xml
    gedit ./etc/hadoop/mapred-site.xml
    <configuration>
    <property>
    <name>mapreduce.framework.name</name>
    <value>yarn</value>
    </property>
    </configuration>

    gedit ./etc/hadoop/yarn-site.xml
    <configuration>
    <property>
    <name>yarn.nodemanager.aux-services</name>
    <value>mapreduce_shuffle</value>
    </property>
    </configuration>

    ./sbin/start-yarn.sh $ 启动YARN
    ./sbin/mr-jobhistory-daemon.sh start historyserver # 开启历史服务器,才能在Web中查看任务运行情况


    [hadoop@localhost hadoop]$ jps
    11148 JobHistoryServer
    9788 NameNode
    10059 DataNode
    11702 Jps
    10428 SecondaryNameNode
    10991 NodeManager
    10874 ResourceManager


    http://localhost:8088/cluster


    关闭YARN

    ./sbin/stop-yarn.sh
    ./sbin/mr-jobhistory-daemon.sh stop historyserver

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    四、Spark安装

    《Spark快速入门指南 – Spark安装与基础使用》- http://dblab.xmu.edu.cn/blog/spark-quick-start-guide/

    下载

      spark-1.6.0-bin-hadoop2.6.tgz
      http://d3kbcqa49mib13.cloudfront.net/spark-1.6.0-bin-hadoop2.6.tgz

    解压
      sudo tar -zxf ~/下载/spark-1.6.0-bin-hadoop2.6.tgz -C /usr/local/
      cd /usr/local
      sudo mv ./spark-1.6.0-bin-hadoop2.6/ ./spark
      sudo chown -R hadoop:hadoop ./spark # 此处的 hadoop 为你的用户名

    安装后,需要在 ./conf/spark-env.sh 中修改 Spark 的 Classpath,执行如下命令拷贝一个配置文件:
      cd /usr/local/spark
      cp ./conf/spark-env.sh.template ./conf/spark-env.sh

      gedit ./conf/spark-env.sh
      export SPARK_DIST_CLASSPATH=$(/usr/local/hadoop/bin/hadoop classpath)

    全局环境变量:
    sudo gedit /etc/profile
    source /etc/profile
    export JAVA_HOME=/usr/local/java
    export HADOOP_HOME=/usr/hadoop
    export SCALA_HOME=/usr/lib/scala-2.10.4
    export SPARK_HOME=/usr/local/spark


    配置Spark环境变量
    cd $SPARK_HOME/conf
    cp spark-env.sh.template spark-env.sh
    gedit spark-env.sh

    spark-env.sh配置

    export SCALA_HOME=/usr/lib/scala-2.10.4
    export HADOOP_HOME=/usr/hadoop
    export HADOOP_CONF_DIR=/usr/local/hadoop/etc/hadoop
    export SPARK_HOME=/usr/local/spark
    export SPARK_PID_DIR=$SPARK_HOME/tmp
    export SPARK_DIST_CLASSPATH=$(/usr/local/hadoop/bin/hadoop classpath)

    export SPARK_MASTER_IP=127.0.0.1
    export SPARK_MASTER_PORT=7077
    export SPARK_MASTER_WEBUI_PORT=8099

    export SPARK_WORKER_CORES=1 //每个Worker使用的CPU核数
    export SPARK_WORKER_INSTANCES=1 //每个Slave中启动几个Worker实例
    export SPARK_WORKER_MEMORY=512m //每个Worker使用多大的内存
    export SPARK_WORKER_WEBUI_PORT=8081 //Worker的WebUI端口号
    export SPARK_EXECUTOR_CORES=1 //每个Executor使用使用的核数
    export SPARK_EXECUTOR_MEMORY=128m //每个Executor使用的内存

    export SPARK_CLASSPATH=$SPARK_HOME/conf/:$SPARK_HOME/lib/*:/usr/local/hadoop/lib/native:$SPARK_CLASSPATH

     

    运行Spark示例

    Spark 的安装目录(/usr/local/spark)为当前路径

    cd /usr/local/spark
    ./bin/run-example SparkPi 2>&1 | grep "Pi is roughly"


    Python 版本的 SparkPi 则需要通过 spark-submit 运行:
    ./bin/spark-submit examples/src/main/python/pi.py 2>&1 | grep "Pi is roughly"

    Hadoop和YARN上运行示例

    cd /etc/local/hadoop

    ./sbin/start-dfs.sh
    ./sbin/start-yarn.sh

    运行示例
    cd /usr/local/spark
    bin/spark-submit --master yarn ./examples/src/main/python/wordcount.py file:///usr/local/spark/LICENSE

    (快照:运行成功Spark示例)

    通过 Spark Shell 进行交互分析

    ./bin/spark-shell

    val textFile = sc.textFile("file:///usr/local/spark/README.md")
    // textFile: org.apache.spark.rdd.RDD[String] = MapPartitionsRDD[1] at textFile at <console>:27

    textFile.count() // RDD 中的 item 数量,对于文本文件,就是总行数
    // res0: Long = 95

    textFile.first() // RDD 中的第一个 item,对于文本文件,就是第一行内容
    // res1: String = # Apache Spark

    val linesWithSpark = textFile.filter(line => line.contains("Spark")) // 筛选出包含 Spark 的行

    linesWithSpark.count() // 统计行数
    // res4: Long = 17

    textFile.filter(line => line.contains("Spark")).count() // 统计包含 Spark 的行数
    // res4: Long = 17

    RDD的更多操作

    textFile.map(line => line.split(" ").size).reduce((a, b) => if (a > b) a else b)
    // res5: Int = 14

    import java.lang.Math
    textFile.map(line => line.split(" ").size).reduce((a, b) => Math.max(a, b))
    // res6: Int = 14

    val wordCounts = textFile.flatMap(line => line.split(" ")).map(word => (word, 1)).reduceByKey((a, b) => a + b) // 实现单词统计
    // wordCounts: org.apache.spark.rdd.RDD[(String, Int)] = ShuffledRDD[4] at reduceByKey at <console>:29
    wordCounts.collect() // 输出单词统计结果
    // res7: Array[(String, Int)] = Array((package,1), (For,2), (Programs,1), (processing.,1), (Because,1), (The,1)...)

    Spark SQL 和 DataFrames

    Spark Streaming

    方式一:

    wget http://downloads.sourceforge.net/project/netcat/netcat/0.6.1/netcat-0.6.1-1.i386.rpm -O ~/netcat-0.6.1-1.i386.rpm # 下载
    sudo rpm -iUv ~/netcat-0.6.1-1.i386.rpm # 安装

    方式二:

    wget http://sourceforge.NET/projects/netcat/files/netcat/0.7.1/netcat-0.7.1-1.i386.rpm
    rpm -ihv netcat-0.7.1-1.i386.rpm
    yum list glibc*
    rpm -ihv netcat-0.7.1-1.i386.rpm

    # 记为终端 1
    nc -l -p 9999

    # 需要另外开启一个终端,记为终端 2,然后运行如下命令
    /usr/local/spark/bin/run-example streaming.NetworkWordCount localhost 9999 2>/dev/null

    (快照:完成Spark Streaming实例)


    关闭 Spark 调试信息

    把spark/conf/log4j.properties下的
    log4j.rootCategory=【Warn】=> 【ERROR】
    log4j.logger.org.spark-project.jetty=【Warn】=> 【ERROR】


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    五、Scala安装

    安装scala 2.10.4:下载scala,http://www.scala-lang.org/,下载scala-2.10.4.tgz,并复制到/usr/lib
    sudo tar -zxf scala-2.10.4.tgz -C /usr/lib

    采用全局设置方法,修改etc/profile,是所有用户的共用的环境变量
    sudo gedit /etc/profile
    export SCALA_HOME=/usr/lib/scala-2.10.4
    export PATH=$SCALA_HOME/bin:$PATH

    source /etc/profile
    scala -version

    [hadoop@localhost 下载]$ scala -version
    Scala code runner version 2.10.4 -- Copyright 2002-2013, LAMP/EPFL
    ——————————————————————————————————————————————————

    六、CentOS中安装IntelliJ IDEA

    参考:http://dongxicheng.org/framework-on-yarn/apache-spark-intellij-idea/

    Spark集成开发环境搭建

    ● 《linux系统下IntelliJ IDEA的安装及使用》 - http://www.linuxdiyf.com/linux/19143.html
    不建议大家使用eclipse开发spark程序和阅读源代码,推荐使用Intellij IDEA

    ● 下载IDEA14.0.5:
    http://confluence.jetbrains.com/display/IntelliJIDEA/Previous+IntelliJ+IDEA+Releases
    http://download.jetbrains.8686c.com/idea/ideaIU-14.0.5.tar.gz

    https://download.jetbrains.8686c.com/idea/ideaIU-2016.2.5-no-jdk.tar.gz(只支持JDK1.8以上)

    Unsupported Java Version: Cannot start under Java 1.7.0_79-b15: Java 1.8 or later is required.


    解压,进入到解压后文件夹的bin目录下执行
    tar -zxvf ideaIU-14.tar.gz -C /usr/intellijIDEA
    export IDEA_JDK=/usr/local/java/jdk1.7.0_79
    ./idea.sh

    key:IDEA
    value:61156-YRN2M-5MNCN-NZ8D2-7B4EW-U12L4

    安装Scala插件

    http://www.linuxdiyf.com/linux/19143.html

    下载地址:http://plugins.jetbrains.com/files/1347/19005/scala-intellij-bin-1.4.zip

    安装插件后,在启动界面中选择创建新项目,弹出的界面中将会出现"Scala"类型项目,如下图,选择scala-》scala

    点击next,就如以下界面,project name自己随便起的名字,把自己安装的scala和jdk选中,注意,在选择scala版本是一定不要选择2.11.X版本,那样后续会出大错!完成后,点击Finish

    然后再File下选择project Structure,然后进入如下界面,进入后点击Libraries,在右边框后没任何信息,然后点击“+”号,进入你安装spark时候解压的spark-XXX-bin-hadoopXX下,在lib目录下,选择spark-assembly-XXX-hadoopXX.jar,结果如下图所示,然后点击Apply,最后点击ok

    Spark开发环境配置及流程(Intellij IDEA)

    《Intellij安装scala插件详解》
    http://blog.csdn.net/a2011480169/article/details/52712421
    从上面显示的信息是: Updatated: 2016/7/13
    于是我们到下面的网站去找匹配的插件: http://plugins.jetbrains.com/plugin/?idea&id=1347
    当我们下载完插件之后: 把下载的.zip格式的scala插件放到Intellij的安装的plugins目录下;
    再安装刚刚放到Intellij的plugins目录下的scala插件(注:直接安装zip文件)即可。

    搭建Spark开发环境
    在intellij IDEA中创建scala project,并依次选择“File”–> “project structure” –> “Libraries”,选择“+”,将spark-hadoop 对应的包导入

    《Spark入门实战系列--3.Spark编程模型(下)--IDEA搭建及实》
    http://www.cnblogs.com/shishanyuan/p/4721120.html

    scala示例代码

    package class3
    import org.apache.spark.SparkConf
    import org.apache.spark.SparkContext
    
    object WordConut {
    
      def main(args: Array[String]) {
    
        val conf = new SparkConf().setAppName("TrySparkStreaming").setMaster("local[2]")
        val sc = new SparkContext(conf)
    
        val txtFile = "/root/test"
        val txtData = sc.textFile(txtFile)
    
        txtData.cache()
        txtData.count()
    
        val wcData = txtData.flatMap { line => line.split(",") }.map { word => (word, 1) }.reduceByKey(_ + _)
    
        wcData.collect().foreach(println)
    
        sc.stop
    
      }
    
    }

    ——————————————————————————————————————————————————

    Spark使用HDFS数据处理

    [hadoop@localhost spark]$ hdfs dfs -put LICENSE /zhaohang
    hdfs dfs -ls
    hdfs dfs -cat /zhaohang | wc -l

    cd /usr/local/spark/bin
    ./pyspark --master yarn

    lines=sc.textFile("hdfs://localhost:9000/zhaohang",1)
    16/11/17 19:36:34 INFO storage.MemoryStore: Block broadcast_0 stored as values in memory (estimated size 228.8 KB, free 228.8 KB)
    16/11/17 19:36:34 INFO storage.MemoryStore: Block broadcast_0_piece0 stored as bytes in memory (estimated size 19.5 KB, free 248.3 KB)
    16/11/17 19:36:34 INFO storage.BlockManagerInfo: Added broadcast_0_piece0 in memory on 10.211.55.8:60185 (size: 19.5 KB, free: 511.5 MB)
    16/11/17 19:36:34 INFO spark.SparkContext: Created broadcast 0 from textFile at NativeMethodAccessorImpl.java:-2

    temp1 = lines.flatMap(lambda x:x.split(' '))

    temp1.collect()
    map = temp1.map(lambda x: (x,1))
    map.collect()


    rdd = sc.parallelize([1,2,3,4],2)
    def f(iterator): yield sum(iterator)
    rdd.mapPartitions(f).collect() //[3,7]

    rdd = sc.parallelize(["a","b","c"])

    test = rdd.flatMap(lambda x:(x,1))
    test.count()

    sorted(test.collect()) //[1, 1, 1, 'a', 'b', 'c']


    Spark界面:http://localhost:8088/proxy/application_1479381551764_0002/jobs/

    关闭YARN及HDFS

    cd /usr/local/hadoop
    ./sbin/stop-dfs.sh
    ./sbin/stop-yarn.sh

    ——————————————————————————————————————————————————

    Spark SQL示例

    开启Hadoop和YARN
    cd /usr/local/hadoop
    ./sbin/start-dfs.sh
    ./sbin/start-yarn.sh
     
    查看JSON示例数据
    cd /usr/local/spark
    cat ./examples/src/main/resources/people.json
     
    启动Spark命令行
    cd /usr/local/spark
    ./bin/spark-shell
     
    执行如下命令导入数据源
    val df = sqlContext.read.json("file:///usr/local/spark/examples/src/main/resources/people.json")
    df.show()
     
    DataFrames 处理结构化数据的一些基本操作
    df.select("name").show() // 只显示 "name" 列
    df.select(df("name"), df("age") + 1).show() // 将 "age" 加 1
    df.filter(df("age") > 21).show() # 条件语句
    df.groupBy("age").count().show() // groupBy 操作
     
    使用 SQL 语句来进行操作
    df.registerTempTable("people") // 将 DataFrame 注册为临时表 people
    val result = sqlContext.sql("SELECT name, age FROM people WHERE age >= 13 AND age <= 19") // 执行 SQL 查询
    result.show() // 输出结果
     
    关闭Hadoop和YARN
    cd /usr/local/hadoop
    ./sbin/stop-dfs.sh
    ./sbin/stop-yarn.sh

    ——————————————————————————————————————————————————

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  • 原文地址:https://www.cnblogs.com/lsx1993/p/6072380.html
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