public static String htmlspecialchars(String input) {
        StringBuffer filtered = new StringBuffer(input.length());
        char c;
        for (int i = 0; i < input.length(); i++) {
            c = input.charAt(i);
            switch (c) {
                case '<':
                    filtered.append("&lt;");
                    break;
                case '>':
                    filtered.append("&gt;");
                    break;
                case '"':
                    filtered.append("&quot;");
                    break;
                case '&':
                    filtered.append("&amp;");
                    break;
                default:
                    filtered.append(c);
            }
        }
        return (filtered.toString());
    }