* @return the MIME type for the extension, or "application/octet-stream" if not found
     * @throws IOException if there is an error processing the MIME mappings
     */
    public String getMimeType(final String extension) throws IOException {
        return getMimeType(extension, "application/octet-stream");
    }

    /**
     * Returns the MIME type for the given file extension with a custom default.
     *

            assertEquals("text/html", mimeMap.getMimeType("html"));
            assertEquals("text/html", mimeMap.getMimeType("htm"));
            assertEquals("image/jpeg", mimeMap.getMimeType("jpg"));
            assertEquals("image/jpeg", mimeMap.getMimeType("jpeg"));
            assertEquals("image/gif", mimeMap.getMimeType("gif"));
            assertEquals("image/png", mimeMap.getMimeType("png"));
        }

        assertEquals("http://example.com/document.pdf", responseData.getUrl());

        responseData.setMimeType("application/pdf");
        assertEquals("application/pdf", responseData.getMimeType());

        responseData.setCharSet("UTF-8");
        assertEquals("UTF-8", responseData.getCharSet());

        responseData.setHttpStatusCode(200);
        assertEquals(200, responseData.getHttpStatusCode());

        if (extractorFactory == null) {
            throw new FessSystemException("Could not find extractorFactory.");
        }
        final Extractor extractor = extractorFactory.getExtractor(responseData.getMimeType());
        if (logger.isDebugEnabled()) {
            logger.debug("url={}, extractor={}", responseData.getUrl(), extractor);
        }
        return extractor;
    }

        if (extractorFactory == null) {
            throw new FessSystemException("Could not find extractorFactory.");
        }
        Extractor extractor = extractorFactory.getExtractor(responseData.getMimeType());
        if (extractor == null) {
            extractor = ComponentUtil.getComponent("tikaExtractor");
            if (extractor == null) {
                throw new FessSystemException("Could not find tikaExtractor.");