从上面源码可以看出doService方法里也是做了许多准备工作，可以看出Spring将localeResolvder、themeResolver等设置在request中，最后传入doDispatch方法，跟进源码：

protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {
    HttpServletRequest processedRequest = request;
    HandlerExecutionChain mappedHandler = null;
    boolean multipartRequestParsed = false;

    WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);

    try {
        ModelAndView mv = null;
        Exception dispatchException = null;

        try {
            // 如果request是MultipartContent类型的话则转为MultipartHttpServletRequest类型
            processedRequest = checkMultipart(request);
            multipartRequestParsed = (processedRequest != request);

            // 根据request寻找对应的Handler
            mappedHandler = getHandler(processedRequest);
            if (mappedHandler == null || mappedHandler.getHandler() == null) {
                // 找不到Handler则返回错误信息
                noHandlerFound(processedRequest, response);
                return;
            }

            // 根据handler找对应的HandlerAdapter
            HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());

            // 如果当前handler支持last-modified头处理
            String method = request.getMethod();
            boolean isGet = "GET".equals(method);
            if (isGet || "HEAD".equals(method)) {
                long lastModified = ha.getLastModified(request, mappedHandler.getHandler());
                if (logger.isDebugEnabled()) {
                    logger.debug("Last-Modified value for [" + getRequestUri(request) + "] is: " + lastModified);
                }
                if (new ServletWebRequest(request, response).checkNotModified(lastModified) && isGet) {
                    return;
                }
            }

            if (!mappedHandler.applyPreHandle(processedRequest, response)) {
                return;
            }