How to join file paths in Java

The paths to files and directories vary between operating systems. For example, in Windows, backslashes (\) are used as separators, whereas in Unix-based systems, forward slash (/)is used.

When joining the file paths, we should write generic code that will work on both of these operating systems.

Using Java.io.File

The File class in Java’s IO library provides platform-independent methods which are used to manipulate file paths.

Following is the example:

import java.io.File;

public class FilePathJoinExample {

    public static void main(String[] args) {
        // Define two path components
        String parentDir = "C:/Users/";
        String fileName = "example.txt";

        // Use File to join the paths
        File file = new File(parentDir, fileName);

        // Get the joined path as a string
        String fullPath = file.getPath();

        System.out.println("Joined Path: " + fullPath);
    }
}

Explanation:

In the above example, we created a File object by passing the parent directory and file name as arguments to the constructor. Finally, using the getPath() method, we get the joined path as a string.

Note: As an alternative, we can also join the paths using string concatenation, as shown in the below example, but this may not work in all operating systems. As mentioned above, each operating system has its own way of representing the paths.

public class FilePathJoinExample {

    public static void main(String[] args) {
        // Define two path components
        String parentDir = "C:/Users/";
        String fileName = "example.txt";

        // Join the paths using string concatenation
        String fullPath = parentDir + fileName;

        System.out.println("Joined Path: " + fullPath);
    }
}