Java Path Normalize normalize(String path)

Description

Normalize a relative URI path that may have relative values ("/./", "/../", and so on ) it it.

License

Apache License

Parameter

Parameter	Description
path	Relative path to be normalized

Return

The normalized path or null if the path cannot be normalized

Declaration

public static String normalize(String path) 

Method Source Code

//package com.java2s;
/*// w  w w.j av a 2 s. c o  m
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

public class Main {
    /**
     * Normalize a relative URI path that may have relative values ("/./",
     * "/../", and so on ) it it.  <strong>WARNING</strong> - This method is
     * useful only for normalizing application-generated paths.  It does not
     * try to perform security checks for malicious input.
     *
     * @param path Relative path to be normalized
     *
     * @return The normalized path or <code>null</code> if the path cannot be
     *         normalized
     */
    public static String normalize(String path) {
        return normalize(path, true);
    }

    /**
     * Normalize a relative URI path that may have relative values ("/./",
     * "/../", and so on ) it it.  <strong>WARNING</strong> - This method is
     * useful only for normalizing application-generated paths.  It does not
     * try to perform security checks for malicious input.
     *
     * @param path Relative path to be normalized
     * @param replaceBackSlash Should '\\' be replaced with '/'
     *
     * @return The normalized path or <code>null</code> if the path cannot be
     *         normalized
     */
    public static String normalize(String path, boolean replaceBackSlash) {

        if (path == null) {
            return null;
        }

        // Create a place for the normalized path
        String normalized = path;

        if (replaceBackSlash && normalized.indexOf('\\') >= 0)
            normalized = normalized.replace('\\', '/');

        // Add a leading "/" if necessary
        if (!normalized.startsWith("/"))
            normalized = "/" + normalized;

        boolean addedTrailingSlash = false;
        if (normalized.endsWith("/.") || normalized.endsWith("/..")) {
            normalized = normalized + "/";
            addedTrailingSlash = true;
        }

        // Resolve occurrences of "//" in the normalized path
        while (true) {
            int index = normalized.indexOf("//");
            if (index < 0) {
                break;
            }
            normalized = normalized.substring(0, index)
                    + normalized.substring(index + 1);
        }

        // Resolve occurrences of "/./" in the normalized path
        while (true) {
            int index = normalized.indexOf("/./");
            if (index < 0) {
                break;
            }
            normalized = normalized.substring(0, index)
                    + normalized.substring(index + 2);
        }

        // Resolve occurrences of "/../" in the normalized path
        while (true) {
            int index = normalized.indexOf("/../");
            if (index < 0) {
                break;
            }
            if (index == 0) {
                return null; // Trying to go outside our context
            }
            int index2 = normalized.lastIndexOf('/', index - 1);
            normalized = normalized.substring(0, index2)
                    + normalized.substring(index + 3);
        }

        if (normalized.length() > 1 && addedTrailingSlash) {
            // Remove the trailing '/' we added to that input and output are
            // consistent w.r.t. to the presence of the trailing '/'.
            normalized = normalized.substring(0, normalized.length() - 1);
        }

        // Return the normalized path that we have completed
        return normalized;
    }
}

Related

1. normalize(final String path)
2. normalize(final String path)
3. normalize(final String path)
4. normalize(final String pathname)
5. normalize(String path)
6. normalize(String path)
7. normalize(String path)
8. normalize(String path)
9. normalize(String path)