Delete a directory in Kotlin

This post will discuss how to delete a directory and all entries in it with Kotlin.

1. Using `File.deleteRecursively()` function

A simple solution to delete a directory with all its subdirectories is using the File.deleteRecursively() function. It returns true if the directory is successfully deleted; false otherwise. The following code demonstrates its usage:

import java.io.File

fun main() {

val file = File("/var/www/html/")

try {

file.deleteRecursively()

println("Directory deleted successfully.")

} catch (e: Exception) {

e.printStackTrace()

}

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2. Using `Files.walkFileTree()` function

The idea is to walk the file tree using Files.walkFileTree() function, and delete each file using the Files.delete() function. If the file is a subdirectory, delete it after visiting it and deleting all files in it. The following example demonstrates the usage of these functions to delete a directory:

import java.io.File

import java.io.IOException

import java.nio.file.FileVisitResult

import java.nio.file.Files

import java.nio.file.Path

import java.nio.file.SimpleFileVisitor

import java.nio.file.attribute.BasicFileAttributes

fun deleteDirectory(directory: Path) {

if (Files.exists(directory)) {

Files.walkFileTree(directory, object : SimpleFileVisitor<Path>() {

override fun visitFile(path: Path, attr: BasicFileAttributes): FileVisitResult {

Files.delete(path)

return FileVisitResult.CONTINUE

}

override fun postVisitDirectory(path: Path, ex: IOException): FileVisitResult {

Files.delete(path)

return FileVisitResult.CONTINUE

}

})

}

fun main() {

val file = File("/var/www/html/")

try {

deleteDirectory(file.toPath())

println("Directory deleted successfully.")

} catch (e: IOException) {

e.printStackTrace()

}

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3. Using `Files.walk()` function

Alternately, we can walk the file tree in a depth-first manner using the Files.walk(…) function that returns a Stream of Path objects. The following code demonstrates the working of the Files.walk(…) function with the File.delete() function to recursively delete the root directory and all its subdirectories.

Note that Comparator.reverseOrder() is used to ensure the parent directory is deleted after the child (Since the directory is processed depth-first and File.delete() cannot delete a non-empty directory).

import java.io.File

import java.io.IOException

import java.nio.file.Files

import java.nio.file.Path

import java.util.*

fun deleteDirectory(directory: Path?) {

Files.walk(directory)

.sorted(Comparator.reverseOrder())

.map { it.toFile() }

.forEach { it.delete() }

}

fun main() {

val file = File("/var/www/html/")

try {

deleteDirectory(file.toPath())

println("Directory deleted successfully.")

} catch (e: IOException) {

e.printStackTrace()

}

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4. Using `Runtime.exec()` function

Another plausible solution is to execute the remove directory command of the underlying environment. This can be done in Kotlin using the Runtime.exec() convenience function.

import java.io.File

import java.io.IOException

fun deleteDirectory(file: File) {

println(file.absolutePath)

if (file.exists()) {

val cmd = "rm -r " + file.absolutePath

Runtime.getRuntime().exec(cmd)

}

fun main() {

val file = File("/var/www/html/")

try {

deleteDirectory(file)

println("Directory deleted successfully.")

} catch (e: IOException) {

e.printStackTrace()

}

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5. Using `File.delete()` function

Finally, we can write a recursive routine to delete a directory with the File.delete() function. This would translate to a simple code below:

import java.io.File

fun deleteDirectory(file: File) {

if (file.isDirectory) {

val contents = file.listFiles()

for (f in contents) {

deleteDirectory(f)

}

file.delete()

}

fun main() {

val file = File("/var/www/html/")

deleteDirectory(file)

println("Directory deleted successfully.")

}

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That’s all about deleting a directory in Kotlin.

Delete a directory in Kotlin

1. Using File.deleteRecursively() function

2. Using Files.walkFileTree() function

3. Using Files.walk() function

4. Using Runtime.exec() function

5. Using File.delete() function

Share this:

1. Using `File.deleteRecursively()` function

2. Using `Files.walkFileTree()` function

3. Using `Files.walk()` function

4. Using `Runtime.exec()` function

5. Using `File.delete()` function