文章目錄

1. 1. 最常用
2. 2. 匯入特定class的member
3. 3. 例子
   1. 3.1. Play Framework 匯入應用

Import(匯入) 在scala有很多方法

最常用

import jason.playground._
匯入jason.playground package 底下的所有classes and object, 包括package object(package object 的所有member會以static 方面匯入)

匯入特定class的member

import jason.playground.JasonPhone._
匯入jason.playground.Jason 底下的所有member

例子

package jason.playground

object JasonPhone {
  def name() = "Iphone 6"
}

package jason

import jason.playground.JasonPhone

package object playground {
  // static method to be imported into class
  def getName() = "Iphone 6 (from helper method)"

  // align to another object's method
  def nameFromPackageObject() = JasonPhone.name()
}

package jason.program

// this line import classes & object under jason.playground (not recurisly)
import jason.playground._;

// this line import "members" under jason.playground.JasonPhone
// ~ import static in Java
import jason.playground.JasonPhone._;

/**
  * Created by Jason on 1/20/16.
  */
object Main {
  def main(args: Array[String]): Unit = {
    println("I am using: " + JasonPhone.name()) // this is declared in JasonPhone.scala
    println("I am using: " + nameFromPackageObject()); // this is declared in package.scala
    println("I am using: " + name()); // this is a short cut with static import
  }
}

• JasonPhone.name() 由匯入jason.playground._ 而來
• nameFromPackageObject() 由匯入jason.playground._ 而來，是package object裡的method
• name() 由static匯入 jason.playground.JasonPhone._而來，不用打JasonPhone作為prefix

Play Framework 匯入應用

val userForm = Form(  mapping(    "name" -> of[String],    "age" -> of[Int],    "email" -> of[String]  )(User.apply)(User.unapply))
  mapping(    "name" -> of[String],    "age" -> of[Int],    "email" -> of[String]  )(User.apply)(User.unapply)
    "name" -> of[String],
    "age" -> of[Int],
    "email" -> of[String]
  )
)

of 由匯入play.api.data.Forms._ 得來, Forms是一個object定義helper methods