public static String getCharsetFromContentType(String contentType) 
{
        if (contentType == null)
            return (null);
        int start = contentType.indexOf("charset=");
        if (start <  0)
            return (null);
        String encoding = contentType.substring(start + 8);
        int end = encoding.indexOf(';');
        if (end  >= 0)
            encoding = encoding.substring(0, end);
        encoding = encoding.trim();
        if ((encoding.length()  > 2) && (encoding.startsWith("\""))
            && (encoding.endsWith("\"")))
            encoding = encoding.substring(1, encoding.length() - 1);
        return (encoding.trim());
}

Parse the character encoding from the specified content type header. If the content type is null, or there is no explicit character encoding, null is returned.

 public static boolean hasCharset(String type) 
{
        boolean hasCharset = false;
        int len = type.length();
        int index = type.indexOf(';');
        while (index != -1) {
            index++;
            while (index <  len && Character.isSpace(type.charAt(index))) {
                index++;
            }
            if (index+8 <  len
                    && type.charAt(index) == 'c'
                    && type.charAt(index+1) == 'h'
                    && type.charAt(index+2) == 'a'
                    && type.charAt(index+3) == 'r'
                    && type.charAt(index+4) == 's'
                    && type.charAt(index+5) == 'e'
                    && type.charAt(index+6) == 't'
                    && type.charAt(index+7) == '=') {
                hasCharset = true;
                break;
            }
            index = type.indexOf(';', index);
        }
        return hasCharset;
}

Returns true if the given content type contains a charset component, false otherwise.