object WordCount {
  def main(args: Array[String]) {
    val inputFile =  "file:///home/common/coding/coding/Scala/word-count/test.segmented"
    val conf = new SparkConf().setAppName("WordCount").setMaster("local")　　　　#创建一个SparkConf对象来配置应用<br>　　　　#集群URL：告诉Spark连接到哪个集群，local是单机单线程，无需连接到集群，应用名：在集群管理器的用户界面方便找到应用
    val sc = new SparkContext(conf)　　　　　　　　#然后基于这SparkConf创建一个SparkContext对象
    val textFile = sc.textFile(inputFile)　　　　#读取输入的数据
    val wordCount = textFile.flatMap(line => line.split(" ")).map(word => (word, 1)).reduceByKey((a, b) => a + b)　　#切分成单词，转换成键值对并计数
    wordCount.foreach(println)
  }
}

val textFile = sc.textFile(inputFile)

val lines = sc.parallelize(List("pandas", "i like pandas"))

var increase = (x: Int) => x + 1
System.out.println(increase(10))

var list1 = List(1, 2)
list1.foreach((x: Int) => println(x))

ssh XXX@XXX

XXXX.bj

scp 开发机用户名@开发机ip地址:/home/XXXXX/文件 .    #最后一个.表示cd的根目录下

sudo chown -R hduser hadoop hbase-1.2.5/

export PATH=$PATH:/usr/local/hbase/bin

export HBASE_HOME=/usr/local/hbase
export PATH=${HBASE_HOME}/bin:$PATH

cd /usr/local
sudo chown -R hadoop ./hbase

hbase version
HBase 1.2.5...

//常见的写法
var filename = "name"
if (!args.isEmpty)
  filename = args(0)

//比较简洁的写法
var filename1 =
  if (!args.isEmpty) args(0)
  else "name"

//更简洁的写法，不要有中间变量
println(if(!args.isEmpty) args(0) else "name")

package com.scala.first

/**
  * Created by common on 17-4-3.
  */
object Rational {
  def main(args: Array[String]) {

    var r1 = new Rational(1, 2)
    var r2 = new Rational(1)
    System.out.println(r1.toString)
    System.out.println(r1.add(r2).toString)
    var r3 = new Rational(2, 2)
    System.out.println(r3)
    System.out.println(r1 + r3)
  }
}

class Rational(n: Int, d: Int) {
  //检查先决条件，不符合先决条件将抛出IllegalArgumentException
  require(d != 0)
  //最大公约数
  private val g = gcd(n.abs, d.abs)

  private def gcd(a: Int, b: Int): Int = {
    if (b == 0) a else gcd(b, a % b)
  }

  //进行约分
  val numer: Int = n / g
  val denom: Int = d / g

  //辅助构造器
  def this(n: Int) = this(n, 1)

  //定义操作符
  def +(that: Rational): Rational = {
    new Rational(
      numer * that.denom + that.numer * denom,
      denom * that.denom
    )
  }

  //方法重载
  def +(i: Int): Rational = {
    new Rational(
      numer + i * denom, denom
    )
  }

  def *(that: Rational): Rational = {
    new Rational(
      numer * that.numer,
      denom * that.denom
    )
  }

  //方法重载
  override def toString = numer + "/" + denom

  //定义方法
  def add(that: Rational): Rational = {
    new Rational(
      numer * that.denom + that.numer * denom,
      denom * that.denom
    )
  }

  //定义方法，自指向this可写可不写
  def lessThan(that: Rational): Boolean = {
    this.numer * that.denom < that.numer * this.denom
  }


}