8.42. Scala File I/O

Scala performs file writing operations, directly using the I/O class in java ( java.io.File ):

8.42.1. Example #

import java.io.\_
object Test {
   def main(args: Array[String]) {
      val writer = new PrintWriter(new File("test.txt" ))
      writer.write("Novice Tutorial")
      writer.close()
   }
}

Execute the above code and one will be produced in your current directory test.txt file, the content of which is “Rookie course”:

$ scalac Test.scala
$ scala Test
$ cat test.txt
Novice Tutorial

Read user input from the screen #

Sometimes we need to receive instructions entered by the user on the screen to process the program. Examples are as follows:

8.42.2. Example #

import scala.io.\_
object Test {
   def main(args: Array[String]) {
      print("Please enter the Rookie Tutorial official website : " )
      val line = StdIn.readLine()
      println("Thank you, what you entered is: " + line)
   }
}

Post-Scala2.11 version Console.readLine abandoned, using scala.io.StdIn.readLine() method instead of.

Execute the above code, and the following information will be displayed on the screen:

$ scalac Test.scala
$ scala Test
Please enter the Rookie Tutorial official website : www.runoob.com
Thank you, what you entered is: www.runoob.com

Read content from a file #

Reading from a file is very simple. We can use Scala’s Source class andaccompanying objects to read the file. The following example demonstrates reading from a “test.txt” (previously created) file:

8.42.3. Example #

import scala.io.Source
object Test {
   def main(args: Array[String]) {
      println("The file content is:" )
      Source.fromFile("test.txt" ).foreach{
         print
      }
   }
}

Execute the above code, and the output is as follows:

$ scalac Test.scala
$ scala Test
The file content is:
Novice Tutorial