springmvc学习笔记(4)-前端控制器

四面垂杨十里荷，问云何处最花多。画楼南畔夕阳和。
天气乍凉人寂寞，光阴须得酒消磨。且来花里听笙歌。
—-宋·苏轼《浣溪沙·荷花》

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前端控制器接收请求

调用doDispatch方法：

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

         。。。。。
}

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前端控制器调用HandlerMapping（处理器映射器）根据url查找Handler

在doDispatch方法中：

mappedHandler = this.getHandler(processedRequest);

Handler的实现：

protected HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception {
    Iterator var2 = this.handlerMappings.iterator();

    HandlerExecutionChain handler;
    do {
        if (!var2.hasNext()) {
            return null;
        }

        HandlerMapping hm = (HandlerMapping)var2.next();
        if (this.logger.isTraceEnabled()) {
            this.logger.trace("Testing handler map [" + hm + "] in DispatcherServlet with name '" + this.getServletName() + "'");
        }

        handler = hm.getHandler(request);
    } while(handler == null);

    return handler;
}

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调用处理器适配器执行Handler,得到执行的结果ModelAndView mv

在doDispatch方法中：

mv = ha.handle(processedRequest, response, mappedHandler.getHandler());

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视图渲染，将model数据填充到request域

doDispatch->processDispatchResult->render

在render方法中,视图解析得到view:

view = resolveViewName(mv.getViewName(), mv.getModelInternal(), locale, request);

调用view的渲染方法，将model数据填充到request域。在render方法中,调用View接口的render方法。

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