Unescapes a String, replacing &#nn;, <, >, &, ", and &apos to the corresponding characters.

Description

Demo Code

/*//  w ww  .ja  va 2 s .  c  o m
 * $Id: c252e97234599bbc2c9094ce3ee83beaa8e24d93 $
 *
 * This file is part of the iText (R) project.
 * Copyright (c) 1998-2016 iText Group NV
 * Authors: Bruno Lowagie, Paulo Soares, Balder Van Camp, et al.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License version 3
 * as published by the Free Software Foundation with the addition of the
 * following permission added to Section 15 as permitted in Section 7(a):
 * FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
 * ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
 * OF THIRD PARTY RIGHTS
 *
 * 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 Affero General Public License for more details.
 * You should have received a copy of the GNU Affero General Public License
 * along with this program; if not, see http://www.gnu.org/licenses or write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA, 02110-1301 USA, or download the license from the following URL:
 * http://itextpdf.com/terms-of-use/
 *
 * The interactive user interfaces in modified source and object code versions
 * of this program must display Appropriate Legal Notices, as required under
 * Section 5 of the GNU Affero General Public License.
 *
 * In accordance with Section 7(b) of the GNU Affero General Public License,
 * a covered work must retain the producer line in every PDF that is created
 * or manipulated using iText.
 *
 * You can be released from the requirements of the license by purchasing
 * a commercial license. Buying such a license is mandatory as soon as you
 * develop commercial activities involving the iText software without
 * disclosing the source code of your own applications.
 * These activities include: offering paid services to customers as an ASP,
 * serving PDFs on the fly in a web application, shipping iText with a closed
 * source product.
 *
 * For more information, please contact iText Software Corp. at this
 * address: sales@itextpdf.com
 */
//package com.java2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        String s = "java2s.com";
        System.out.println(unescapeXML(s));
    }

    /**
     * Unescapes a String, replacing &#nn;, &lt;, &gt;, &amp;, &quot;,
     * and &apos to the corresponding characters.
     * @param s   a String with entities
     * @return the unescaped string
     */
    public static String unescapeXML(final String s) {
        char[] cc = s.toCharArray();
        int len = cc.length;
        StringBuffer sb = new StringBuffer();
        int pos;
        String esc;
        for (int i = 0; i < len; i++) {
            int c = cc[i];
            if (c == '&') {
                pos = findInArray(';', cc, i + 3);
                if (pos > -1) {
                    esc = new String(cc, i + 1, pos - i - 1);
                    if (esc.startsWith("#")) {
                        esc = esc.substring(1);
                        if (isValidCharacterValue(esc)) {
                            c = (char) Integer.parseInt(esc);
                            i = pos;
                        } else {
                            i = pos;
                            continue;
                        }
                    } else {
                        int tmp = unescape(esc);
                        if (tmp > 0) {
                            c = tmp;
                            i = pos;
                        }
                    }
                }
            }
            sb.append((char) c);
        }
        return sb.toString();
    }

    /**
     * Looks for a character in a character array, starting from a certain position
     * @param needle   the character you're looking for
     * @param haystack   the character array
     * @param start      the start position
     * @return   the position where the character was found, or -1 if it wasn't found.
     */
    public static int findInArray(char needle, char[] haystack, int start) {
        for (int i = start; i < haystack.length; i++) {
            if (haystack[i] == ';')
                return i;
        }
        return -1;
    }

    /**
     * Checks if a character value should be escaped/unescaped.
     * @param   s   the String representation of an integer
     * @return   true if it's OK to escape or unescape this value 
     */
    public static boolean isValidCharacterValue(String s) {
        try {
            int i = Integer.parseInt(s);
            return isValidCharacterValue(i);
        } catch (NumberFormatException nfe) {
            return false;
        }
    }

    /**
     * Checks if a character value should be escaped/unescaped.
     * @param   c   a character value
     * @return   true if it's OK to escape or unescape this value 
     */
    public static boolean isValidCharacterValue(int c) {
        return (c == 0x9 || c == 0xA || c == 0xD || c >= 0x20
                && c <= 0xD7FF || c >= 0xE000 && c <= 0xFFFD || c >= 0x10000
                && c <= 0x10FFFF);
    }

    /**
     * Unescapes 'lt', 'gt', 'apos', 'quote' and 'amp' to the
     * corresponding character values.
     * @param   s   a string representing a character
     * @return   a character value
     */
    public static int unescape(String s) {
        if ("apos".equals(s))
            return '\'';
        if ("quot".equals(s))
            return '"';
        if ("lt".equals(s))
            return '<';
        if ("gt".equals(s))
            return '>';
        if ("amp".equals(s))
            return '&';
        return -1;
    }
}
Unescapes a String, replacing &#nn;, <, >, &, ", and &apos to the corresponding characters. - Java XML

Description

Demo Code

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