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/* * Copyright 2001-2004 The Apache Software Foundation. * * Licensed 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.ByteArrayOutputStream; import java.io.UnsupportedEncodingException; import java.util.BitSet; /** * <p>Implements the 'www-form-urlencoded' encoding scheme, * also misleadingly known as URL encoding.</p> * * <p>For more detailed information please refer to * <a href="http://www.w3.org/TR/html4/interact/forms.html#h-17.13.4.1"> * Chapter 17.13.4 'Form content types'</a> of the * <a href="http://www.w3.org/TR/html4/">HTML 4.01 Specification<a></p> * * <p> * This codec is meant to be a replacement for standard Java classes * {@link java.net.URLEncoder} and {@link java.net.URLDecoder} * on older Java platforms, as these classes in Java versions below * 1.4 rely on the platform's default charset encoding. * </p> * * @author Apache Software Foundation * @since 1.2 * @version $Id: URLCodec.java,v 1.19 2004/03/29 07:59:00 ggregory Exp $ */ public class URLCodec { /** * The default charset used for string decoding and encoding. */ protected String charset = "UTF8"; protected static byte ESCAPE_CHAR = '%'; /** * BitSet of www-form-url safe characters. */ protected static final BitSet WWW_FORM_URL = new BitSet(256); // Static initializer for www_form_url static { // alpha characters for (int i = 'a'; i <= 'z'; i++) { WWW_FORM_URL.set(i); } for (int i = 'A'; i <= 'Z'; i++) { WWW_FORM_URL.set(i); } // numeric characters for (int i = '0'; i <= '9'; i++) { WWW_FORM_URL.set(i); } // special chars WWW_FORM_URL.set('-'); WWW_FORM_URL.set('_'); WWW_FORM_URL.set('.'); WWW_FORM_URL.set('*'); // blank to be replaced with + WWW_FORM_URL.set(' '); } /** * Default constructor. */ public URLCodec() { super(); } /** * Constructor which allows for the selection of a default charset * * @param charset the default string charset to use. */ public URLCodec(String charset) { super(); this.charset = charset; } /** * Encodes an array of bytes into an array of URL safe 7-bit * characters. Unsafe characters are escaped. * * @param urlsafe bitset of characters deemed URL safe * @param bytes array of bytes to convert to URL safe characters * @return array of bytes containing URL safe characters */ public static final byte[] encodeUrl(BitSet urlsafe, byte[] bytes) { if (bytes == null) { return null; } if (urlsafe == null) { urlsafe = WWW_FORM_URL; } ByteArrayOutputStream buffer = new ByteArrayOutputStream(); for (int i = 0; i < bytes.length; i++) { int b = bytes[i]; if (b < 0) { b = 256 + b; } if (urlsafe.get(b)) { if (b == ' ') { b = '+'; } buffer.write(b); } else { buffer.write('%'); char hex1 = Character.toUpperCase(Character.forDigit((b >> 4) & 0xF, 16)); char hex2 = Character.toUpperCase(Character.forDigit(b & 0xF, 16)); buffer.write(hex1); buffer.write(hex2); } } return buffer.toByteArray(); } /** * Decodes an array of URL safe 7-bit characters into an array of * original bytes. Escaped characters are converted back to their * original representation. * * @param bytes array of URL safe characters * @return array of original bytes * @throws DecoderException Thrown if URL decoding is unsuccessful */ public static final byte[] decodeUrl(byte[] bytes) throws Exception { if (bytes == null) { return null; } ByteArrayOutputStream buffer = new ByteArrayOutputStream(); for (int i = 0; i < bytes.length; i++) { int b = bytes[i]; if (b == '+') { buffer.write(' '); } else if (b == '%') { try { int u = Character.digit((char) bytes[++i], 16); int l = Character.digit((char) bytes[++i], 16); if (u == -1 || l == -1) { throw new RuntimeException("Invalid URL encoding"); } buffer.write((char) ((u << 4) + l)); } catch (ArrayIndexOutOfBoundsException e) { throw new RuntimeException("Invalid URL encoding"); } } else { buffer.write(b); } } return buffer.toByteArray(); } /** * Encodes an array of bytes into an array of URL safe 7-bit * characters. Unsafe characters are escaped. * * @param bytes array of bytes to convert to URL safe characters * @return array of bytes containing URL safe characters */ public byte[] encode(byte[] bytes) { return encodeUrl(WWW_FORM_URL, bytes); } /** * Decodes an array of URL safe 7-bit characters into an array of * original bytes. Escaped characters are converted back to their * original representation. * * @param bytes array of URL safe characters * @return array of original bytes * @throws DecoderException Thrown if URL decoding is unsuccessful */ public byte[] decode(byte[] bytes) throws Exception { return decodeUrl(bytes); } /** * Encodes a string into its URL safe form using the specified * string charset. Unsafe characters are escaped. * * @param pString string to convert to a URL safe form * @param charset the charset for pString * @return URL safe string * @throws UnsupportedEncodingException Thrown if charset is not * supported */ public String encode(String pString, String charset) throws UnsupportedEncodingException { if (pString == null) { return null; } return new String(encode(pString.getBytes(charset)), "US-ASCII"); } /** * Encodes a string into its URL safe form using the default string * charset. Unsafe characters are escaped. * * @param pString string to convert to a URL safe form * @return URL safe string * @throws EncoderException Thrown if URL encoding is unsuccessful * * @see #getDefaultCharset() */ public String encode(String pString) throws Exception { if (pString == null) { return null; } try { return encode(pString, getDefaultCharset()); } catch (UnsupportedEncodingException e) { throw new RuntimeException(e.getMessage()); } } /** * Decodes a URL safe string into its original form using the * specified encoding. Escaped characters are converted back * to their original representation. * * @param pString URL safe string to convert into its original form * @param charset the original string charset * @return original string * @throws DecoderException Thrown if URL decoding is unsuccessful * @throws UnsupportedEncodingException Thrown if charset is not * supported */ public String decode(String pString, String charset) throws Exception, UnsupportedEncodingException { if (pString == null) { return null; } return new String(decode(pString.getBytes("US-ASCII")), charset); } /** * Decodes a URL safe string into its original form using the default * string charset. Escaped characters are converted back to their * original representation. * * @param pString URL safe string to convert into its original form * @return original string * @throws DecoderException Thrown if URL decoding is unsuccessful * * @see #getDefaultCharset() */ public String decode(String pString) throws Exception { if (pString == null) { return null; } try { return decode(pString, getDefaultCharset()); } catch (UnsupportedEncodingException e) { throw new RuntimeException(e.getMessage()); } } /** * Encodes an object into its URL safe form. Unsafe characters are * escaped. * * @param pObject string to convert to a URL safe form * @return URL safe object * @throws EncoderException Thrown if URL encoding is not * applicable to objects of this type or * if encoding is unsuccessful */ public Object encode(Object pObject) throws Exception { if (pObject == null) { return null; } else if (pObject instanceof byte[]) { return encode((byte[]) pObject); } else if (pObject instanceof String) { return encode((String) pObject); } else { throw new RuntimeException( "Objects of type " + pObject.getClass().getName() + " cannot be URL encoded"); } } /** * Decodes a URL safe object into its original form. Escaped * characters are converted back to their original representation. * * @param pObject URL safe object to convert into its original form * @return original object * @throws DecoderException Thrown if URL decoding is not * applicable to objects of this type * if decoding is unsuccessful */ public Object decode(Object pObject) throws Exception { if (pObject == null) { return null; } else if (pObject instanceof byte[]) { return decode((byte[]) pObject); } else if (pObject instanceof String) { return decode((String) pObject); } else { throw new RuntimeException( "Objects of type " + pObject.getClass().getName() + " cannot be URL decoded"); } } /** * The default charset used for string decoding and encoding. * * @return the default string charset. */ public String getDefaultCharset() { return this.charset; } }