Write file

使用 java io 的 package，來建立檔案 :
用 PrintWriter

scala> import java.io._
import java.io._

scala> val pw = new PrintWriter(new File("/Volumes/Transcend/scala-test/b.txt"))
pw: java.io.PrintWriter = java.io.PrintWriter@1ee11117

scala> pw.write("您好")

scala> pw.close

用 FileWriter

val file = new File("/Volumes/Transcend/scala-test/c.txt")

scala> val file = new File("/Volumes/Transcend/scala-test/c.txt")
file: java.io.File = /Volumes/Transcend/scala-test/c.txt

scala> val bw = new BufferedWriter(new FileWriter(file))
bw: java.io.BufferedWriter = java.io.BufferedWriter@577953cb

scala> bw.write("Hello 您好啊")

scala> bw.close()

使用第三方元件 better-files :

下載 better-files 的 jar (這邊用 better-files_2.12-3.4.0.jar)

scala> :require better-files_2.12-3.4.0.jar
Added '/Volumes/Transcend/scala-test/better-files_2.12-3.4.0.jar' to classpath.

import better.files :

scala> import better.files._
import better.files._

scala> import java.io.{File => JFile}
import java.io.{File=>JFile}

scala> val file = file"/Volumes/Transcend/scala-test/d.txt"
file: better.files.File = /Volumes/Transcend/scala-test/d.txt

scala> file.overwrite("hello")
res17: file.type = /Volumes/Transcend/scala-test/d.txt

scala> file.appendLine().append("world")
res18: file.type = /Volumes/Transcend/scala-test/d.txt

使用 symbol 的寫法 :

scala> import better.files.Dsl.SymbolicOperations
import better.files.Dsl.SymbolicOperations

scala> import scala.language.existentials
import scala.language.existentials

< 用來覆寫檔案，<< 用來新增一行及內容 :

scala> file < "Hi"
res26: qual$1.file.type forSome { val qual$1: better.files.Dsl.SymbolicOperations } = /Volumes/Transcend/scala-test/d.txt

scala> file << " Daniel"
res27: qual$1.file.type forSome { val qual$1: better.files.Dsl.SymbolicOperations } = /Volumes/Transcend/scala-test/d.txt

換個寫法也可以 :
>: 用來覆寫檔案，>>: 用來新增一行及內容

cala> "Scala" `>:` file
res29: qual$1.file.type forSome { val qual$1: better.files.Dsl.SymbolicOperations } = /Volumes/Transcend/scala-test/d.txt

scala> "Test" >>: file
res31: qual$1.file.type forSome { val qual$1: better.files.Dsl.SymbolicOperations } = /Volumes/Transcend/scala-test/d.txt

better-files 還有許多功能，詳細寫法可以參考下面網址．

總結

• scala 的 io 目前好像比較偏向使用 java io 或著 better files 第三方元件，未來不知道本身會不會提供．

參考資料

better file : https://github.com/pathikrit/better-files