Java Path Relative Get getRelativePath(File a, File b, String pathSep)

Description

get Relative Path

License

Apache License

Declaration

public static String getRelativePath(File a, File b, String pathSep) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

import java.io.File;

import java.util.StringTokenizer;

public class Main {
    public static String getRelativePath(String a, String b, String pathSep) {
        String[] pathA = getPaths(a);
        String[] pathB = getPaths(b);

        // get common root.
        int indexA = -1;
        int indexB = -1;

        for (int i = pathA.length; 0 < i; i--) {
            if (lastIndexOf(pathA[i - 1], pathB) != -1) {
                indexA = i - 1;// w  w  w  .  j a v a2 s .  c om
                indexB = lastIndexOf(pathA[i - 1], pathB);
                break;
            }
        }

        if (indexA == -1 || indexB == -1) {
            return null;
        }

        int pathADistance = pathA.length - (indexA + 1);
        int pathBDistance = pathB.length - (indexB + 1);

        String relativePath = "";
        for (int i = 0; i < pathADistance; i++) {
            relativePath += ".." + pathSep;
        }
        //        if (pathADistance == 0) {
        //            relativePath = "." + File.separator;
        //        }

        String[] pathBComponents = getPathComponents(b);

        String sep = "";
        for (int i = pathB.length - pathBDistance; i < pathB.length; i++) {
            relativePath += sep + pathBComponents[i];
            sep = pathSep;
        }
        return relativePath;
    }

    public static String getRelativePath(String a, String b) {
        return getRelativePath(a, b, File.separator);
    }

    public static String getRelativePath(File a, File b, String pathSep) {
        return getRelativePath(a.getAbsolutePath(), b.getAbsolutePath(), pathSep);
    }

    public static String getRelativePath(File a, File b) {
        return getRelativePath(a.getAbsolutePath(), b.getAbsolutePath(), File.separator);
    }

    private static String[] getPaths(String str) {
        StringTokenizer tokens = new StringTokenizer(str, "\\/", false);
        String[] result = new String[tokens.countTokens()];
        String currentPath = "";
        String pathSep = "";
        for (int i = 0; i < result.length; i++) {
            currentPath = currentPath + pathSep + tokens.nextToken();
            result[i] = currentPath;
            pathSep = File.separator;
        }
        return result;
    }

    private static int lastIndexOf(String str, String[] path) {
        for (int i = path.length; 0 < i; i--) {
            if (path[i - 1].compareTo(str) == 0) {
                return i - 1;
            }
        }
        return -1;
    }

    private static String[] getPathComponents(String str) {
        StringTokenizer tokens = new StringTokenizer(str, "\\/", false);
        String[] result = new String[tokens.countTokens()];
        for (int i = 0; i < result.length; i++) {
            result[i] = tokens.nextToken();
        }
        return result;
    }
}

Related

1. getRelativePath(@Nullable File projectFile, @Nullable File rootFile)
2. getRelativePath(File ancestor, File file)
3. getRelativePath(File base, File absoluteFile)
4. getRelativePath(File base, File file)
5. getRelativePath(File base, File file)