Scala基础概述

官方网站 https://www.scala-lang.org/

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安装开发环境

下载JDK配置JAVA1.8以上开发环境

$ java -version
java version "1.8.0_121"
Java(TM) SE Runtime Environment (build 1.8.0_121-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.121-b13, mixed mode)

下载Scala下载地址 https://www.scala-lang.org/download/

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$ scala -version
Scala code runner version 2.12.8 -- Copyright 2002-2018, LAMP/EPFL and Lightbend, Inc.

scala 历史版本

https://github.com/scala/scala/releases

idea开发IDE的安装

1. 确保安装了 Java 8 JDK (also known as 1.8)
   • Run javac -version on the command line and make sure you seejavac 1.8.___
   • If you don’t have version 1.8 or higher, install the JDK
2. 下载 IntelliJ Community Edition
3. 启动 IntelliJ, 下载安装 Scala 插件，安装插件说明 how to install IntelliJ plugins (search for “Scala” in the plugins menu.)

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创建工程HelloWorld

1. 打开 IntelliJ 然后点击 File => New => Project 2 在左侧菜单栏选择Scala 然后选择右侧选择IDEA

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1. 创建项目 HelloWorld 4 如果没有安装Scala SDK 可以选在安装SDK 版本

Writing code

1. On the Project pane on the left, right-click src and select New => Scala class. If you don’t see Scala class, right-click on HelloWorld and click on Add Framework Support…, select Scala and proceed. If you see Error: library is not specified, you can either click download button, or select the library path manually.
2. Name the class Hello and change the Kind to object.
3. Change the code in the class to the following:

object Hello extends App {
  println("Hello, World!")
}

REPL(Read Eval Print Loop:交互式解释器)

$ scala
Welcome to Scala 2.12.8 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_121).
Type in expressions for evaluation. Or try :help.
scala> var x = 1
x: Int = 1
scala> :q

Maven创建项目

选择org.scals-tools.archetypes:scala-archetype-simple

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<dependency>
      <groupId>org.scala-lang</groupId>
      <artifactId>scala-library</artifactId>
      <version>${scala.version}</version>
 </dependency>