三、SpringMVC之用

程序员文章站 2022-05-20 14:27:19

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看透spring MVC 源代码分析与实践 学习记录

01：客户端请求到前端控制器（即 DispatcherServlet ）:

→ HttpServlet#doService(ServletRequest request, ServletResponse response)
→ FrameworkServlet的doGet，doPost等方法
→ FrameworkServlet#processRequest
→ DispatcherServlet#doService(HttpServletRequest request, HttpServletResponse response)
→ DispatcherServlet#doDispatch(HttpServletRequest request, HttpServletResponse response)

02：查找 Handler

→ mappedHandler = getHandler(processedRequest);
List<HandlerMapping> 遍历HandlerMapping查找Handler
返回值是 HandlerExecutionChain，包含了2部分内容： ① Handler对象、② 拦截器数组。

03:通过 Handler 查找 HandlerAdapter

→ HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());

04:前置

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

05:HandlerAdapter执行Handler处理业务，返回ModelAndView

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

06:后置

→ mappedHandler.applyPostHandle(processedRequest, response, mv);

07：渲染视图，响应客户端

→ processDispatchResult(processedRequest, response, mappedHandler, mv, dispatchException);
→ render(mv, request, response);
视图解析器（ViewResolver）返回真正的视图对象（View）
→ view=resolveViewName(mv.getViewName(),mv.getModelInternal(),locale,request);
→ view.render(mv.getModelInternal(), request, response);
→ InternalResourceView#renderMergedOutputModel(mergedModel, getRequestToExpose(request), response);
→ RequestDispatcher rd = getRequestDispatcher(request, dispatcherPath);
→ if (useInclude(request, response)) {…
rd.include(request, response);
} else {…
rd.forward(request, response);
}

springMVC以一个servlet为入口，即 DispatcherServlet 。
三、SpringMVC之用