Java Path Relative getRelativeFile(File target, File base)

Description

Returns the path of one file relative to another.

License

LGPL

Parameter

Parameter	Description
target	The target file
base	The base file

Return

The target's file relative to the base file

Declaration

public static File getRelativeFile(File target, File base) 

Method Source Code

//package com.java2s;
/**//from   w w w  . j  a v a2s  .c  o  m
 * Copyright 2009-2012 Three Crickets LLC.
 * <p>
 * The contents of this file are subject to the terms of the LGPL version 3.0:
 * http://www.gnu.org/copyleft/lesser.html
 * <p>
 * Alternatively, you can obtain a royalty free commercial license with less
 * limitations, transferable or non-transferable, directly from Three Crickets
 * at http://threecrickets.com/
 */

import java.io.File;

import java.util.regex.Pattern;

public class Main {
    /**
     * Returns the path of one file relative to another.
     * 
     * @param target
     *        The target file
     * @param base
     *        The base file
     * @return The target's file relative to the base file
     */
    public static File getRelativeFile(File target, File base) {
        return new File(getRelativePath(target.getAbsolutePath(), base.getAbsolutePath()));
    }

    /**
     * Returns the path of one file relative to another.
     * 
     * @param target
     *        The target path
     * @param base
     *        The base path
     * @return The target's path relative to the base path
     */
    public static String getRelativePath(String target, String base) {
        // See:
        // http://stackoverflow.com/questions/204784/how-to-construct-a-relative-path-in-java-from-two-absolute-paths-or-urls

        String split = Pattern.quote(File.separator);
        String[] baseSegments = base.split(split);
        String[] targetSegments = target.split(split);
        StringBuilder result = new StringBuilder();

        // Skip common segments
        int index = 0;
        for (; index < targetSegments.length && index < baseSegments.length; ++index) {
            if (!targetSegments[index].equals(baseSegments[index]))
                break;
        }

        // Backtrack to base directory
        int length = baseSegments.length;
        if (index != length) {
            for (int i = index; i < length; ++i) {
                // "." segments have no effect
                if (!baseSegments[i].equals("."))
                    result.append(".." + File.separator);
            }
        }

        for (; index < targetSegments.length; ++index)
            result.append(targetSegments[index] + File.separator);

        // Remove final path separator
        if (!target.endsWith(File.separator))
            result.delete(result.length() - 1, result.length());

        return result.toString();
    }
}

Related

1. getRelativeChildDirectory(String parent, String child)
2. getRelativeDirectoryPath(String in_filePath, String in_basePath)
3. getRelativeFile(File parent, final String s2)
4. getRelativeFile(File source, String path)
5. getRelativeFile(File subj, File relativeTo)
6. getRelativeFile(File target, File baseDirectory)
7. getRelativeFile(File targetFile, File baseFile)
8. getRelativeFile(java.io.File srcFile, int upCount, String... childPaths)
9. getRelativeFile(String baseDir, String fileName)