Kotlin – How to read File with Kotlin language

https://grokonez.com/kotlin/kotlin-read-file-kotlin-language

Kotlin – How to read File with Kotlin language

This tutorial shows you how to read File in Kotlin using InputStream or BufferedReader.

I. Technology

• Java 1.8
• Kotlin 1.1.2

  II. Overview

  1. Goal

  Read file: all lines/by line using InputStream or BufferedReader or File directly.

  2. Steps to do

• Create:
• InputStream from File, then get BufferedReader using bufferedReader() method
• BufferedReader from File.
• Use:
• Closeable.use() method with Reader.readText() method inside block. Closeable.use() will automatically close the input at the end of the lambda's execution:

  
  String = (Reader implements Closeable).use(Reader.readText())
  

• Reader.useLines() method with Kotlin Sequence (a sequence of all the lines) inside block. Reader.useLines() will automatically close the reader once the processing is complete:

  
  Reader.useLines(block: Sequence)
  

• File.useLines() method with Kotlin Sequence (a sequence of all the lines) inside block. It will close the reader once the processing is complete:

  
  File.useLines(block: Sequence)
  

• File.readLines() method to return a List<String>:

  
  File.readLines()
  

  III. Practice

  0. kotlin.txt

More at:

https://grokonez.com/kotlin/kotlin-read-file-kotlin-language

Kotlin – How to read File with Kotlin language