How to create directory in Java

In Java, we can use the NIO Files.createDirectory to create a directory or Files.createDirectories to create a directory including all nonexistent parent directories.

  try {

    Path path = Paths.get("/home/mkyong/a/b/c/");

    //java.nio.file.Files;
    Files.createDirectories(path);

    System.out.println("Directory is created!");

  } catch (IOException e) {

    System.err.println("Failed to create directory!" + e.getMessage());

  }

1. Create Directory – Java NIO

1.1 We can use Files.createDirectory to create a directory.

• If the parent directories not exist, throws NoSuchFileException.
• If the directory exists, throws FileAlreadyExistsException.
• If IO errors, throws IOException.

  Path path = Paths.get("/home/mkyong/test2/");
  Files.createDirectory(path);

1.2 We can use Files.createDirectories creates a directory including all nonexistent parent directories.

• If the parent directories not exist, create it first.
• If the directory exists, no exception thrown.
• If IO errors, throws IOException

  Path path = Paths.get("/home/mkyong/test2/test3/test4/");
  Files.createDirectories(path);

1.3 This example uses Files.createDirectories to create a directory /test4/ including all nonexistent parent directories /test2/test3/.

package com.mkyong.io.directory;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class DirectoryCreate1 {

    public static void main(String[] args) {

        String dir = "/home/mkyong/test2/test3/test4/";

        try {

            Path path = Paths.get(file);

            Files.createDirectories(path);

            System.out.println("Directory is created!");

            //Files.createDirectory(path);

        } catch (IOException e) {
            System.err.println("Failed to create directory!" + e.getMessage());
        }

    }
}

2. Create Directory – Legacy IO

For legacy IO java.io.File, the similar methods are file.mkdir() to create a directory, and file.mkdirs() to create a directory including all nonexistent parent directories.

Both file.mkdir() and file.mkdirs() returns a boolean, true if success to create the directory, fail otherwise, no exception thrown.

package com.mkyong.io.directory;

import java.io.File;

public class DirectoryCreate2 {

    public static void main(String[] args) {

        String dir = "/home/mkyong/test2/test3/test4/";

        File file = new File(dir);

        // true if the directory was created, false otherwise
        if (file.mkdirs()) {
            System.out.println("Directory is created!");
        } else {
            System.out.println("Failed to create directory!");
        }

    }

}

In legacy IO, the lack of exception thrown in creating directory makes developers very hard to debug or understand why we cannot create a directory, and this is one of the reasons Java releases a new java.nio.Files to throw a proper exception.

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References

• Files JavaDoc
• File JavaDoc