Java tutorial
/* JSPWiki - a JSP-based WikiWiki clone. 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. */ import java.io.UnsupportedEncodingException; import java.security.SecureRandom; import java.util.Properties; import java.util.Random; /** * Contains a number of static utility methods. */ // FIXME3.0: Move to the "util" package public final class TextUtil { static final String HEX_DIGITS = "0123456789ABCDEF"; /** * Private constructor prevents instantiation. */ private TextUtil() { } /** * java.net.URLEncoder.encode() method in JDK < 1.4 is buggy. This duplicates * its functionality. * @param rs the string to encode * @return the URL-encoded string */ protected static String urlEncode(byte[] rs) { StringBuffer result = new StringBuffer(rs.length * 2); // Does the URLEncoding. We could use the java.net one, but // it does not eat byte[]s. for (int i = 0; i < rs.length; i++) { char c = (char) rs[i]; switch (c) { case '_': case '.': case '*': case '-': case '/': result.append(c); break; case ' ': result.append('+'); break; default: if ((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9')) { result.append(c); } else { result.append('%'); result.append(HEX_DIGITS.charAt((c & 0xF0) >> 4)); result.append(HEX_DIGITS.charAt(c & 0x0F)); } } } // for return result.toString(); } /** * URL encoder does not handle all characters correctly. * See <A HREF="http://developer.java.sun.com/developer/bugParade/bugs/4257115.html"> * Bug parade, bug #4257115</A> for more information. * <P> * Thanks to CJB for this fix. * * @param bytes The byte array containing the bytes of the string * @param encoding The encoding in which the string should be interpreted * @return A decoded String * * @throws UnsupportedEncodingException If the encoding is unknown. * @throws IllegalArgumentException If the byte array is not a valid string. */ protected static String urlDecode(byte[] bytes, String encoding) throws UnsupportedEncodingException, IllegalArgumentException { if (bytes == null) { return null; } byte[] decodeBytes = new byte[bytes.length]; int decodedByteCount = 0; try { for (int count = 0; count < bytes.length; count++) { switch (bytes[count]) { case '+': decodeBytes[decodedByteCount++] = (byte) ' '; break; case '%': decodeBytes[decodedByteCount++] = (byte) ((HEX_DIGITS.indexOf(bytes[++count]) << 4) + (HEX_DIGITS.indexOf(bytes[++count]))); break; default: decodeBytes[decodedByteCount++] = bytes[count]; } } } catch (IndexOutOfBoundsException ae) { throw new IllegalArgumentException("Malformed UTF-8 string?"); } String processedPageName = null; try { processedPageName = new String(decodeBytes, 0, decodedByteCount, encoding); } catch (UnsupportedEncodingException e) { throw new UnsupportedEncodingException("UTF-8 encoding not supported on this platform"); } return processedPageName; } /** * As java.net.URLEncoder class, but this does it in UTF8 character set. * * @param text The text to decode * @return An URLEncoded string. */ public static String urlEncodeUTF8(String text) { // If text is null, just return an empty string if (text == null) { return ""; } byte[] rs; try { rs = text.getBytes("UTF-8"); return urlEncode(rs); } catch (UnsupportedEncodingException e) { throw new Exception("UTF-8 not supported!?!"); } } /** * As java.net.URLDecoder class, but for UTF-8 strings. null is a safe * value and returns null. * * @param utf8 The UTF-8 encoded string * @return A plain, normal string. */ public static String urlDecodeUTF8(String utf8) { String rs = null; if (utf8 == null) return null; try { rs = urlDecode(utf8.getBytes("ISO-8859-1"), "UTF-8"); } catch (UnsupportedEncodingException e) { throw new Exception("UTF-8 or ISO-8859-1 not supported!?!"); } return rs; } /** * Provides encoded version of string depending on encoding. * Encoding may be UTF-8 or ISO-8859-1 (default). * * <p>This implementation is the same as in * FileSystemProvider.mangleName(). * * @param data A string to encode * @param encoding The encoding in which to encode * @return An URL encoded string. */ public static String urlEncode(String data, String encoding) { // Presumably, the same caveats apply as in FileSystemProvider. // Don't see why it would be horribly kludgy, though. if ("UTF-8".equals(encoding)) { return TextUtil.urlEncodeUTF8(data); } try { return TextUtil.urlEncode(data.getBytes(encoding)); } catch (UnsupportedEncodingException uee) { throw new Exception("Could not encode String into" + encoding); } } /** * Provides decoded version of string depending on encoding. * Encoding may be UTF-8 or ISO-8859-1 (default). * * <p>This implementation is the same as in * FileSystemProvider.unmangleName(). * * @param data The URL-encoded string to decode * @param encoding The encoding to use * @return A decoded string. * @throws UnsupportedEncodingException If the encoding is unknown * @throws IllegalArgumentException If the data cannot be decoded. */ public static String urlDecode(String data, String encoding) throws UnsupportedEncodingException, IllegalArgumentException { // Presumably, the same caveats apply as in FileSystemProvider. // Don't see why it would be horribly kludgy, though. if ("UTF-8".equals(encoding)) { return TextUtil.urlDecodeUTF8(data); } try { return TextUtil.urlDecode(data.getBytes(encoding), encoding); } catch (UnsupportedEncodingException uee) { throw new Exception("Could not decode String into" + encoding); } } }