Computes a relative path between to Files - Java File Path IO

Java examples for File Path IO:Path

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Description

Computes a relative path between to Files

Demo Code

// Copyright (C) 2001-2012 Michael Bayne, et al.
//package com.java2s;
import java.io.File;
import java.io.IOException;

public class Main {
    /**/*from  w w w . j a v a  2  s.  co  m*/
     * Computes a relative path between to Files
     *
     * @param file the file we're referencing
     * @param relativeTo the path from which we want to refer to the file
     */
    public static String computeRelativePath(File file, File relativeTo)
            throws IOException {
        String[] realDirs = getCanonicalPathElements(file);
        String[] relativeToDirs = getCanonicalPathElements(relativeTo);

        // Eliminate the common root
        int common = 0;
        for (; common < realDirs.length && common < relativeToDirs.length; common++) {
            if (!realDirs[common].equals(relativeToDirs[common])) {
                break;
            }
        }

        String relativePath = "";

        // For each remaining level in the file path, add a ..
        for (int ii = 0; ii < (realDirs.length - common); ii++) {
            relativePath += ".." + File.separator;
        }

        // For each level in the resource path, add the path
        for (; common < relativeToDirs.length; common++) {
            relativePath += relativeToDirs[common] + File.separator;
        }

        return relativePath;
    }

    /**
     * Gets the individual path elements building up the canonical path to the given file.
     */
    public static String[] getCanonicalPathElements(File file)
            throws IOException {
        file = file.getCanonicalFile();

        // If we were a file, get its parent
        if (!file.isDirectory()) {
            file = file.getParentFile();
        }

        return file.getPath().split(File.separator);
    }
}

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