3 Ways to Get Relative Paths in Java: URI, String, and NIO

Unlock the Power of Relative Paths in Java

When working with file systems, understanding how to navigate between directories is crucial. One essential concept in this context is the relative path, which allows you to specify a path relative to a starting point. In this article, we’ll explore three different methods for obtaining a relative path from two absolute paths in Java.

Method 1: Leveraging the URI Class

The URI class provides a convenient way to convert absolute paths to relative paths. By utilizing the toURI(), relativize(), and getPath() methods, you can easily extract the relative path from two absolute paths.

Consider the following example:
java
URI absolutePath1 = new URI("file:///absolute/path1");
URI absolutePath2 = new URI("file:///absolute/path2");
URI relativePath = absolutePath1.relativize(absolutePath2);
String relativePathStr = relativePath.getPath();

This approach simplifies the process of obtaining a relative path, making it an attractive solution for many use cases.

Method 2: String Manipulation

Another approach involves converting the file paths to strings and manipulating them to extract the relative path. By using the substring() method, you can remove the common prefix from the absolute paths, resulting in the relative path.

Here’s an example:
java
String absolutePath1 = "file:///absolute/path1";
String absolutePath2 = "file:///absolute/path2";
int index = absolutePath1.indexOf(absolutePath2);
String relativePathStr = absolutePath1.substring(index + absolutePath2.length());

While this method requires more manual effort, it can be effective in certain situations.

Method 3: Java NIO File Package

The java.nio.file package provides a more modern approach to working with file systems. The Path interface offers a relativize() method, which can be used to obtain a relative path from two absolute paths.

Take a look at this example:
java
Path absolutePath1 = Paths.get("file:///absolute/path1");
Path absolutePath2 = Paths.get("file:///absolute/path2");
Path relativePath = absolutePath1.relativize(absolutePath2);
String relativePathStr = relativePath.toString();

This method is particularly useful when working with the Java NIO file package.

By mastering these three methods, you’ll be well-equipped to handle a wide range of file system-related tasks in Java. Whether you’re working with URI classes, string manipulation, or the Java NIO file package, understanding how to obtain relative paths is an essential skill for any Java developer.