scala是一門函式式的面向物件的語言，它執行在java虛擬機器上。
eg1、
示例程式碼：
scala>var helloWorld = "hello" + " world" 
println(helloWorld)scala>val again = " again" 
helloWorld = helloWorld + again
println(helloWorld)
輸出：
hello world
hello world again
eg2、定義函式 def
示例程式碼：
def square(a: Int) = a * adef squareWithBlock(a: Int) = { a * a}
 
val squareVal = (a: Int) => a * a （這裡是將Int整數a對映為a*a的函式）def addOne(f: Int => Int, arg: Int) = f(arg) + 1（這裡的=>表示所對映的型別，這就表示這個引數要是一個引數為int型別，返回的型別也是int 的方法）println("square(2):" + square(2))
println("squareWithBlock(2):" + squareWithBlock(2))
println("squareVal(2):" + squareVal(2))
println("addOne(squareVal,2):" + addOne(squareVal, 2))
 
輸出結果：
square(2):4
squareWithBlock(2):4
squareVal(2):4
addOne(squareVal,2):5
eg3、
程式碼例項：
import scala.reflect.io.File
import java.util.Scannerdef withScanner(f: File, op: Scanner => Unit) = {// 沒有返回值的預設返回的是Unit
    val scanner = new Scanner(f.bufferedReader)
    try {
        op(scanner)
    } finally {
 
        scanner.close()
    }
}withScanner(File("/proc/self/stat"),
    scanner => println("pid is " + scanner.next()))
其中widthScanner封裝了try-Catch塊，呼叫者不用再close了
返回結果：
pid is 6065
eg4、定義類
class Persion(val firstName: String, val lastName: String) {  //通過class定義類，val來定義欄位，在類中def定義類中的函式，其中firstName和lastName會自動生成get,set方法    private var _age = 0
    def age = _age  //這是一個方法
    def age_=(newAge: Int) = _age = newAge    def fullName() = firstName + " " + lastName    override def toString() = fullName()//這是覆蓋toString方法
}val obama: Persion = new Persion("Barack", "Obama")//用new的方式建立類println("Persion: " + obama)
println("firstName: " + obama.firstName)
println("lastName: " + obama.lastName)
obama.age_=(51)
println("age: " + obama.age)
返回結果：
Persion: Barack Obama
firstName: Barack
lastName: Obama
age: 51
eg5、
執行例項：
def withClose(closeAble: { def close(): Unit }, //這裡是將{def close():Unit}這個方法作為一種型別
    op: { def close(): Unit } => Unit) {
    try {
        op(closeAble)
    } finally {
        closeAble.close()
    }
}class Connection {
    def close() = println("close Connection")
}val conn: Connection = new Connection()
withClose(conn, conn =>
    println("do something with Connection"))
執行結果：
do something with Connection
close Connection
eg6、柯里化（currying）技術
def add(x:Int, y:Int) = x + y是普通的函式
def add(x:Int) = (y:Int) => x + y
是柯里化後的函式，相當於返回一個匿名函式表示式。
def add(x:Int)(y:Int) = x + y
是簡化寫法

def withClose(closeAble: { def close(): Unit })//小白一枚，還是沒有弄明白為什麼我建立這個方法時候總是無效的？？？
    (op: { def close(): Unit } => Unit) {
    try {
        op(closeAble)
    } finally {
        closeAble.close()
    }
}

class Connection {
    def close() = println("close Connection")
}
val conn: Connection = new Connection()
withClose(conn)(conn =>
    println("do something with Connection"))

eg7、泛型

def withClose[A <: { def close(): Unit }, B](closeAble: A)//這裡的A表示的是{def close():Unit}的子型別
  (f: A => B): B =
  try {
    f(closeAble)
  } finally {
    closeAble.close()
  }
class Connection {
  def close() = println("close Connection")
}
val conn: Connection = new Connection()
val msg = withClose(conn) { conn =>
  {
    println("do something with Connection")
    "123456"
  }
}
println(msg)

返回結果：

do something with Connection
close Connection
123456

eg8 Traits 相當於java中的介面implements

trait ForEachAble[A] {
  def iterator: java.util.Iterator[A]
  def foreach(f: A => Unit) = {
    val iter = iterator
    while (iter.hasNext)
      f(iter.next)
  }
}

trait JsonAble {
  def toJson() =
    scala.util.parsing.json.JSONFormat.defaultFormatter(this)
}

val list = new java.util.ArrayList[Int]() with ForEachAble[Int] width JsonAble 
list.add(1); list.add(2)
println("For each: "); list.foreach(x => println(x))
//println("Json: " + list.toJson())