Java tutorial
import java.io.File; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.util.Iterator; import java.util.LinkedList; import java.util.StringTokenizer; /* Derby - Class org.apache.derby.iapi.util.PropertyUtil 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 uri containing ../ and ./ paths. * * @param uri The uri path to normalize * @return The normalized uri */ public static String normalize(String uri) { if ("".equals(uri)) { return uri; } int leadingSlashes; for (leadingSlashes = 0; leadingSlashes < uri.length() && uri.charAt(leadingSlashes) == '/'; ++leadingSlashes) { } boolean isDir = (uri.charAt(uri.length() - 1) == '/'); StringTokenizer st = new StringTokenizer(uri, "/"); LinkedList clean = new LinkedList(); while (st.hasMoreTokens()) { String token = st.nextToken(); if ("..".equals(token)) { if (!clean.isEmpty() && !"..".equals(clean.getLast())) { clean.removeLast(); if (!st.hasMoreTokens()) { isDir = true; } } else { clean.add(".."); } } else if (!".".equals(token) && !"".equals(token)) { clean.add(token); } } StringBuffer sb = new StringBuffer(); while (leadingSlashes-- > 0) { sb.append('/'); } for (Iterator it = clean.iterator(); it.hasNext();) { sb.append(it.next()); if (it.hasNext()) { sb.append('/'); } } if (isDir && sb.length() > 0 && sb.charAt(sb.length() - 1) != '/') { sb.append('/'); } return sb.toString(); } }