File Paths in Java

Here’s the translation of the Go code example to Java, with explanations in Markdown format suitable for Hugo:

The java.nio.file.Paths class provides methods to work with file paths in a way that is portable between operating systems. For example, dir/file on Linux vs. dir\file on Windows.

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

public class FilePaths {
    public static void main(String[] args) {
        // Paths.get() should be used to construct paths in a portable way.
        // It takes any number of arguments and constructs a hierarchical path from them.
        Path p = Paths.get("dir1", "dir2", "filename");
        System.out.println("p: " + p);

        // You should always use Paths.get() instead of concatenating
        // '/' or '\' manually. In addition to providing portability,
        // Paths.get() will also normalize paths by removing superfluous
        // separators and directory changes.
        System.out.println(Paths.get("dir1//", "filename"));
        System.out.println(Paths.get("dir1/../dir1", "filename"));

        // getParent() and getFileName() can be used to split a path to the
        // directory and the file.
        System.out.println("p.getParent(): " + p.getParent());
        System.out.println("p.getFileName(): " + p.getFileName());

        // We can check whether a path is absolute.
        System.out.println(Paths.get("dir/file").isAbsolute());
        System.out.println(Paths.get("/dir/file").isAbsolute());

        String filename = "config.json";

        // Some file names have extensions following a dot. We can
        // split the extension out of such names.
        int dotIndex = filename.lastIndexOf('.');
        String ext = (dotIndex == -1) ? "" : filename.substring(dotIndex);
        System.out.println(ext);

        // To find the file's name with the extension removed,
        // use substring.
        System.out.println(filename.substring(0, filename.length() - ext.length()));

        // relativize() finds a relative path between a base and a target.
        // It returns the target if it cannot be made relative to base.
        Path base = Paths.get("a/b");
        Path target = Paths.get("a/b/t/file");
        System.out.println(base.relativize(target));

        target = Paths.get("a/c/t/file");
        System.out.println(base.relativize(target));
    }
}

To run the program, compile and execute it:

$ javac FilePaths.java
$ java FilePaths
p: dir1\dir2\filename
dir1\filename
dir1\filename
p.getParent(): dir1\dir2
p.getFileName(): filename
false
true
.json
config
t\file
..\..\c\t\file

Note: The output may vary slightly depending on the operating system due to different path separators.

In this Java version:

We use the java.nio.file.Paths and java.nio.file.Path classes for path operations.
Paths.get() is used instead of filepath.Join().
getParent() and getFileName() replace filepath.Dir() and filepath.Base().
isAbsolute() is used instead of filepath.IsAbs().
For file extension operations, we use string manipulation methods as Java doesn’t have a direct equivalent to filepath.Ext().
relativize() is used instead of filepath.Rel().

The overall structure and explanation have been maintained, adapted to Java’s syntax and conventions.

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File Paths in Java