Java > Files NIO

Files NIO in Java

The java.nio.file package in Java provides enhanced file handling capabilities with efficient methods for reading, writing, and managing files. The Files class in this package offers a rich set of utility methods for file operations.

Understanding Path, Paths, and Files

Path Interface

• The Path interface represents the location of a file or directory in the file system.
• It is obtained using Paths.get() method for flexible path handling.
• It is more efficient and versatile than the traditional File class.

Paths Class

• The Paths class is a utility class used to create Path objects.
• The most common method is Paths.get() which converts string paths into Path instances.
• Supports both relative and absolute file paths for seamless path handling.

Example:

import java.nio.file.Path;
import java.nio.file.Paths;

public class PathExample {
    public static void main(String[] args) {
        Path path = Paths.get("example_nio.txt");
        System.out.println("File Name: " + path.getFileName());
        System.out.println("Root: " + path.getRoot());
        System.out.println("Parent: " + path.getParent());
    }
}

Files Class

• The Files class provides static methods for file creation, deletion, copying, moving, and reading/writing data.
• It simplifies file operations using modern APIs like Path.

Common Methods in Files Class

Operation	Package	Class	Method
Create File	java.nio.file	Files	createFile()
Create Directory	java.nio.file	Files	createDirectory()
Copy File	java.nio.file	Files	copy()
Move File	java.nio.file	Files	move()
Delete File	java.nio.file	Files	delete()
Read File	java.nio.file	Files	readAllLines()
Write to File	java.nio.file	Files	write()

Example: Creating a File Using Files.createFile()

package com.vvsk.fullstack.files;

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

public class CreateFileNIOExample {
    public static void main(String[] args) {
        Path path = Paths.get("example_nio.txt");
        try {
            Files.createFile(path);
            System.out.println("File created successfully.");
        } catch (IOException e) {
            System.out.println("Error creating file: " + e.getMessage());
        }
    }
}

Example: Reading a File Using Files.readAllLines()

package com.vvsk.fullstack.files;

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

public class ReadFileNIOExample {
    public static void main(String[] args) {
        Path path = Paths.get("example_nio.txt");
        try {
            List<String> lines = Files.readAllLines(path);
            lines.forEach(System.out::println);
        } catch (IOException e) {
            System.out.println("Error reading file: " + e.getMessage());
        }
    }
}

Example: Writing to a File Using Files.write()

package com.vvsk.fullstack.files;

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

public class WriteFileNIOExample {
    public static void main(String[] args) {
        Path path = Paths.get("example_nio.txt");
        try {
            Files.write(path, Arrays.asList("Hello, NIO World!", "Java NIO makes file handling easy."));
            System.out.println("Data written successfully.");
        } catch (IOException e) {
            System.out.println("Error writing to file: " + e.getMessage());
        }
    }
}

Best Practices for Using Files in Java NIO

✅ Use Paths.get() for platform-independent file paths.
✅ Leverage try-with-resources to manage file resources efficiently.
✅ Handle exceptions like IOException and FileAlreadyExistsException carefully.
✅ Prefer Files.copy() for copying files efficiently with permissions preserved.

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