public class AccessInterceptor implements HandlerInterceptor {

    ...

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object o) throws Exception {
        logger.info("We now intercept that url " + request.getRequestURI());

	...

	// Проверка доступа для текущего пользователя
        if (validatePageNumber(pageNum, hashName)) {
            // Создание снэпшота
	    createImage(pageNum, hashName);
            return true;
        }

        response.sendError(HttpServletResponse.SC_UNAUTHORIZED);
        return false;
    }

    private void createImage(int pageNum, String hashName) throws FileNotFoundException, IOException {
        String snapshotPath = ConfigProperties.SOURCE_FOLDER + "/" + ConfigProperties.SNAPSHOT_FORMAT + "/" + hashName + "/";
        File snapshotFolder = new File(snapshotPath);
        snapshotFolder.mkdirs();
        File snapshot = new File(snapshotPath + pageNum);
        // Если снэпшота нет, то создаем его
        if (!snapshot.isFile()) {
            _parser.getImage(hashName, pageNum);
            // Проверяем существование файла
	    if (!snapshot.isFile()) {
                logger.error("SNAPSHOT " + snapshotPath + imageName + " didn't generate!!!");
            }
        }
    }

    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {
        logger.info("After handling the request " + request.getRequestURI());
        String url = request.getRequestURI();
        String snapshotPath = ConfigProperties.SOURCE_FOLDER + url;
        File snapshot = new File(snapshotPath);
        // Еще раз проверяем существование файла        	
	if (snapshot.isFile()) {
            logger.info("exist");
        } else {
            logger.info("don't exist");
        }
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
        logger.info("After rendering the view " + request.getRequestURI());
    }

}

	
       <mvc:interceptors>
		<mvc:interceptor>
			<mvc:mapping path="/PNG/**" />
			<bean id="AccessInterceptor"
				class="com.web.interceptors.PdfViewerAccessInterceptor" />
		</mvc:interceptor>
	</mvc:interceptors>

	<mvc:resources mapping="/PNG/**" location="/PNG/" />