Java String Unescape unescape(String aValue)

Description

Unescapes hex values in a URI query value.

License

Open Source License

Parameter

Parameter	Description
aValue	the string to be unescaped. May be null.

Return

the unescaped string, or null if aValue was null.

Declaration

public static String unescape(String aValue) 

Method Source Code

//package com.java2s;
/*******************************************************************************
 * Copyright 2000, 2006 Visual Systems Corporation.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Public License version 2
 * which accompanies this distribution in a file named "COPYING".
 * //from   w  w w .j a va  2s  . c  om
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *      
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *      
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *******************************************************************************/

public class Main {
    /**
     * Unescapes hex values in a URI query value.
     *
     * @param aValue the string to be unescaped. May be null.
     *
     * @return the unescaped string, or null if aValue was null.
     */
    public static String unescape(String aValue) {
        if (aValue == null) {
            return aValue;
        }

        char[] chars = aValue.toCharArray();
        StringBuffer buf = new StringBuffer(chars.length);
        for (int i = 0; i < chars.length; i++) {
            if (chars[i] == '%') {
                ++i;
                buf.append((char) ((charToNybble(chars[i++]) << 4) | charToNybble(chars[i])));
            } else {
                buf.append(chars[i]);
            }
        }

        return buf.toString();
    }

    private static int charToNybble(char c) {
        if (Character.isDigit(c)) {
            return c - '0';
        }

        return (Character.toUpperCase(c) - 'A') + 10;
    }
}

Related

1. unescape(final String str, final char escapeChar)
2. unescape(final String string, final char quoteChar)
3. unescape(final String text)
4. unescape(final String[] inval, final Character escapeChar)
5. unescape(String aString)
6. unescape(String data)
7. unescape(String elt)
8. unescape(String entry)
9. unescape(String escaped)