The FileSystem class is part of the java.nio.file package.It represents a file system, which provides access to file stores, file attributes, and files themselves.
FileSystem acts as a factory for Path objects.It abstracts the underlying file system (e.g., Windows, Unix, ZIP file system).You don’t create FileSystem instances directly; instead, you obtain them via the FileSystems utility class.
How to Obtain a FileSystem Instance
Commonly Used Methods
Simple Program Using FileSystem
Problem Statement:
Write a Java program that obtains the default file system and prints all root directories on the system.
import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.Path;
public class SimpleFileSystemExample {
public static void main(String[] args) {
FileSystem fs = FileSystems.getDefault();
System.out.println("Root directories in the default file system:");
for (Path root : fs.getRootDirectories()) {
System.out.println(root);
}
}
}Problem Statement:
Create a Java program that:
- Uses the default
FileSystem. - Lists all file stores (disks/partitions) and prints their name, type, total space, and usable space.
- Lists all root directories.
- Reads and prints the supported file attribute views.
- Checks if the file system is read-only or open.
import java.nio.file.*;
import java.nio.file.attribute.FileStoreAttributeView;
import java.io.IOException;
public class FileSystemDetails {
public static void main(String[] args) {
FileSystem fs = FileSystems.getDefault();
System.out.println("Listing file stores:");
for (FileStore store : fs.getFileStores()) {
try {
System.out.println("Name: " + store.name());
System.out.println("Type: " + store.type());
System.out.println("Total Space (bytes): " + store.getTotalSpace());
System.out.println("Usable Space (bytes): " + store.getUsableSpace());
System.out.println("-------------------------");
} catch (IOException e) {
System.err.println("Error getting store info: " + e.getMessage());
}
}
System.out.println("\nRoot directories:");
for (Path root : fs.getRootDirectories()) {
System.out.println(root);
}
System.out.println("\nSupported File Attribute Views:");
for (String view : fs.supportedFileAttributeViews()) {
System.out.println(view);
}
System.out.println("\nIs the file system read-only? " + fs.isReadOnly());
System.out.println("Is the file system open? " + fs.isOpen());
}
}FileSystem abstracts the actual file system of the OS or custom file systems.
- Use
FileSystems.getDefault()to get the default system. - Provides methods to access roots, file stores, attribute views.
- Useful for querying system disk info and creating/manipulating
Pathobjects.