springmvc学习笔记(4)-前端控制器
标签： springmvc
本文通过前端控制器源码分析springmvc执行过程
1.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;
。。。。。
}2.前端控制器调用HandlerMapping（处理器映射器）根据url查找Handler
// Determine handler for the current request.
mappedHandler = getHandler(processedRequest);/**
* Return the HandlerExecutionChain for this request.
* <p>Tries all handler mappings in order.
* @param request current HTTP request
* @return the HandlerExecutionChain, or {@code 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.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
// Actually invoke the handler.
mv = ha.handle(processedRequest, response, mappedHandler.getHandler());4.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
// We need to resolve the view name.
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);程序我也没细读，感觉分析比较浅，很多还没弄懂，等我系统阅读源码后会整理一篇好点的。