Spring MVC的流程及源码分析

1.Spring MVC通过前置控制器DispatcherServlet处理客户端请求,这里用到了DispatcherServlet的doService方法中的doDispatch

DispatcherServlet.java

	protected void doService(HttpServletRequest request, HttpServletResponse response) throws Exception {
		logRequest(request);`
		.....省略其他代码
try {
			doDispatch(request, response);
		}

		....省略其他代码
}

2.在doDispatch方法中，通过将request请求从handlerMappings中获取一个handler，这里返回的是一个叫HandlerExecutionChain

	protected HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception {
		if (this.handlerMappings != null) {
			for (HandlerMapping mapping : this.handlerMappings) {
				HandlerExecutionChain handler = mapping.getHandler(request);
				if (handler != null) {
					return handler;
				}
			}
		}
		return null;
	}

3.用handler获取HandlerAdapter

	
	protected HandlerAdapter getHandlerAdapter(Object handler) throws ServletException {
		if (this.handlerAdapters != null) {
			for (HandlerAdapter adapter : this.handlerAdapters) {
				if (adapter.supports(handler)) {
					return adapter;
				}
			}
		}
		throw new ServletException("No adapter for handler [" + handler +
				"]: The DispatcherServlet configuration needs to include a HandlerAdapter that supports this handler");
	}

4.执行HandlerExecutionChain中的拦截器操作

5.通过HandlerAdapter执行真正的handler操作，返回ModleAndView

6.获取默认的viewName

7.执行拦截器的postHandle方法

mappedHandler.applyPostHandle(processedRequest, response, mv);

8.通过viewResolvers返回view

参考文档： https://blog.csdn.net/u013219087/article/details/80649650