springmvc學習筆記(4)-前端控制器

springmvc學習筆記(4)-前端控制器

本文通過前端控制器源碼分析springmvc執行過程

1.前端控制器接收請求

調用doDispatch方法

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

         。。。。。
}

2.前端控制器調用HandlerMapping（處理器映射器）根據url查找Handler

// Determine handler for the current request.
mappedHandler = getHandler(processedRequest);

/**
     * Return the HandlerExecutionChain for this request.
     * 

Tries all handler mappings in order. * @param request current HTTP request * @return the HandlerExecutionChain, or [email protected] null} if no handler could be found */ protected HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception { for (HandlerMapping hm : this.handlerMappings) { if (logger.isTraceEnabled()) { logger.trace( "Testing handler map [" + hm + "] in DispatcherServlet with name '" + getServletName() + "'"); } HandlerExecutionChain handler = hm.getHandler(request); if (handler != null) { return handler; } } return null; }

3.調用處理器適配器執行Handler,得到執行的結果ModelAndView mv

在doDispatch方法中

// Actually invoke the handler.
mv = ha.handle(processedRequest, response, mappedHandler.getHandler());

4.視圖渲染，將model數據填充到request域

doDispatch->processDispatchResult->render

在render方法中,視圖解析得到view

// We need to resolve the view name.
view = resolveViewName(mv.getViewName(), mv.getModelInternal(), locale, request);

調用view的渲染方法，將model數據填充到request域

在render方法中,調用View接口的render方法

view.render(mv.getModelInternal(), request, response);

程序我也沒細讀，感覺分析比較淺，很多還沒弄懂，等我系統閱讀源碼後會整理一篇好點的。