Java tutorial
/* * JBoss, Home of Professional Open Source * Copyright 2006, Red Hat Middleware LLC, and individual contributors * as indicated by the @author tags. * See the copyright.txt in the distribution for a * full listing of individual contributors. * This copyrighted material is made available to anyone wishing to use, * modify, copy, or redistribute it subject to the terms and conditions * of the GNU Lesser General Public License, v. 2.1. * This program is distributed in the hope that it will be useful, but WITHOUT A * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. * You should have received a copy of the GNU Lesser General Public License, * v.2.1 along with this distribution; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, * MA 02110-1301, USA. * * (C) 2005-2006, * @author JBoss Inc. */ /* * Copyright (C) 1998, 1999, 2000, 2001, * * Arjuna Solutions Limited, * Newcastle upon Tyne, * Tyne and Wear, * UK. * * $Id: FileLocator.java 2342 2006-03-30 13:06:17Z $ */ import java.io.File; import java.net.URL; import java.io.FileNotFoundException; import java.net.MalformedURLException; /** * The FileLocator class provides a common method for locating files. * If not passed an absolute filename (starting with the string "abs://"), * it searches for the file in the order: * in the directory specified by the system property user.dir * in the directory specified by the system property user.home * in the directory specified by the system property java.home * using the getResource() method * * @author Julian Coleman * @version $Id: FileLocator.java 2342 2006-03-30 13:06:17Z $ * @since JTS 3.0. */ public class FileLocator { /** * Locate the specific file. * Return the (URL decoded) abolute pathname to the file or null. */ public static String locateFile(String findFile) throws FileNotFoundException { URL url; String fullPathName; StringBuffer decodedPathName; int pos, len, start; if (findFile == null) throw new FileNotFoundException("locateFile: null file name"); if (findFile.startsWith(absolutePath)) return findFile.substring(absolutePath.length()); if ((fullPathName = locateByProperty(findFile)) != null) return fullPathName; if ((url = locateByResource(findFile)) != null) { /* * The URL that we receive from getResource /might/ have ' ' * (space) characters converted to "%20" strings. However, * it doesn't have other URL encoding (e.g '+' characters are * kept intact), so we'll just convert all "%20" strings to * ' ' characters and hope for the best. */ fullPathName = url.getFile(); pos = 0; len = fullPathName.length(); start = 0; decodedPathName = new StringBuffer(); while ((pos = fullPathName.indexOf(pct20, start)) != -1) { decodedPathName.append(fullPathName.substring(start, pos)); decodedPathName.append(' '); start = pos + pct20len; } if (start < len) decodedPathName.append(fullPathName.substring(start, len)); fullPathName = decodedPathName.toString(); if (platformIsWindows()) fullPathName = fullPathName.substring(1, fullPathName.length()); return fullPathName; } throw new FileNotFoundException("locateFile: file not found: " + findFile); } /** * Locate the specific file. * Return the file name in URL form or null. */ public static URL locateURL(String findFile) throws FileNotFoundException { URL url; String fullPathName; if (findFile == null) throw new FileNotFoundException("locateURL: null file name"); try { if (findFile.startsWith(absolutePath)) { return (new URL("file:/" + findFile.substring(absolutePath.length()))); } if ((fullPathName = locateByProperty(findFile)) != null) { if (platformIsWindows()) url = new URL("file:/" + fullPathName); else url = new URL("file:" + fullPathName); return url; } //TODO: TR: used for testing: return new URL(findFile); } catch (MalformedURLException e) { System.err.println("locateURL: URL creation problem"); throw new FileNotFoundException("locateURL: URL creation problem"); } if ((url = locateByResource(findFile)) != null) return url; throw new FileNotFoundException("locateURL: file not found: " + findFile); } /** * Search for a file using the properties: user.dir, user.home, java.home * Returns absolute path name or null. */ private static synchronized String locateByProperty(String findFile) { String fullPathName = null; String dir = null; File f = null; if (findFile == null) return null; try { // System.err.println("Searching in user.dir for: " + findFile); dir = System.getProperty("user.dir"); if (dir != null) { fullPathName = dir + File.separatorChar + findFile; f = new File(fullPathName); } if (f != null && f.exists()) { // System.err.println("Found in user.dir"); return fullPathName; } dir = System.getProperty("user.home"); if (dir != null) { fullPathName = dir + File.separatorChar + findFile; f = new File(fullPathName); } if (f != null && f.exists()) { // System.err.println("Found in user.home"); return fullPathName; } dir = System.getProperty("java.home"); if (dir != null) { fullPathName = dir + File.separatorChar + findFile; f = new File(fullPathName); } if (f != null && f.exists()) { // System.err.println("Found in java.home"); return fullPathName; } } catch (Exception e) { return null; } return null; } /** * Search for a file using the properties: user.dir, user.home, java.home * Returns URL or null. */ private static URL locateByResource(String findFile) { ClassLoader loader = Thread.currentThread().getContextClassLoader(); URL url = loader.getResource(findFile); if (url == null) { url = FileLocator.class.getResource("/" + findFile); } // System.err.println("Search succeeded via getResource()"); return url; } /* * Check the file separator to see if we're on a Windows platform. * * @return boolean True if the platform is Windows, false otherwise. */ private static boolean platformIsWindows() { if (File.separatorChar == '\\') { return true; } return false; } private static final String absolutePath = "abs://"; private static final String pct20 = "%20"; private static final int pct20len = 3; }