Java Path Relative Get getRelativePath(String basePath, String pathToRelativize)

Description

get Relative Path

License

BSD License

Declaration

public static String getRelativePath(String basePath,
            String pathToRelativize) throws IOException 

Method Source Code

//package com.java2s;
/*/*from  ww  w  .j  a va2 s  .co m*/
 * [The "BSD licence"]
 * Copyright (c) 2010 Ben Gruver
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;

public class Main {
    public static String getRelativePath(String basePath,
            String pathToRelativize) throws IOException {
        File baseFile = new File(basePath);
        if (baseFile.isFile()) {
            baseFile = baseFile.getParentFile();
        }

        return getRelativeFileInternal(baseFile.getCanonicalFile(),
                new File(pathToRelativize).getCanonicalFile());
    }

    static String getRelativeFileInternal(File canonicalBaseFile,
            File canonicalFileToRelativize) {
        ArrayList<String> basePath = getPathComponents(canonicalBaseFile);
        ArrayList<String> pathToRelativize = getPathComponents(canonicalFileToRelativize);

        //if the roots aren't the same (i.e. different drives on a windows machine), we can't construct a relative
        //path from one to the other, so just return the canonical file
        if (!basePath.get(0).equals(pathToRelativize.get(0))) {
            return canonicalFileToRelativize.getPath();
        }

        int commonDirs;
        StringBuilder sb = new StringBuilder();

        for (commonDirs = 1; commonDirs < basePath.size()
                && commonDirs < pathToRelativize.size(); commonDirs++) {
            if (!basePath.get(commonDirs).equals(
                    pathToRelativize.get(commonDirs))) {
                break;
            }
        }

        boolean first = true;
        for (int i = commonDirs; i < basePath.size(); i++) {
            if (!first) {
                sb.append(File.separatorChar);
            } else {
                first = false;
            }

            sb.append("..");
        }

        first = true;
        for (int i = commonDirs; i < pathToRelativize.size(); i++) {
            if (first) {
                if (sb.length() != 0) {
                    sb.append(File.separatorChar);
                }
                first = false;
            } else {
                sb.append(File.separatorChar);
            }

            sb.append(pathToRelativize.get(i));
        }

        if (sb.length() == 0) {
            return ".";
        }

        return sb.toString();
    }

    private static ArrayList<String> getPathComponents(File file) {
        ArrayList<String> path = new ArrayList<String>();

        while (file != null) {
            File parentFile = file.getParentFile();

            if (parentFile == null) {
                path.add(0, file.getPath());
            } else {
                path.add(0, file.getName());
            }

            file = parentFile;
        }

        return path;
    }
}

Related

1. getRelativePath(final String base, final File targetFile)
2. getRelativePath(String base, String fullPath)
3. getRelativePath(String base, String relative, boolean isBaseFile)
4. getRelativePath(String baseFullPath, File file)
5. getRelativePath(String basePath, String path)
6. getRelativePath(String fileName, String projFile)
7. getRelativePath(String filePath, String basePath)
8. getRelativePath(String from, String to)
9. getRelativePath(String parent, String child)