SpringMVC源码分析

DispatchServlet

  众所周知，SpringMVC的核心Servlet是DispatchServlet，于是找到它的关键方法doDispatch来进行深入地分析：

doDispatch

protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {

		**//检查是否携带文件上传（request中会带有multipart信息）**
		processedRequest = checkMultipart(request);
		**//最重要的一个方法：找到对应的Controller，并且执行相应的方法。
		mappedHandler = getHandler(processedRequest);
				HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());
				String method = request.getMethod();
				// **执行找到的Handler的具体方法
				mv = ha.handle(processedRequest, response, mappedHandler.getHandler());
				applyDefaultViewName(processedRequest, mv);
				mappedHandler.applyPostHandle(processedRequest, response, mv);
			}
			processDispatchResult(processedRequest, response, mappedHandler, mv, dispatchException);
		}

		}
	}

• getHandler方法调用链：HandlerExecutionChain handler = hm.getHandler(request);--->Object handler = getHandlerInternal(request);--->AbstractHandlerMethodMapping的HandlerMethod handlerMethod = lookupHandlerMethod(lookupPath, request);--->List directPathMatches = this.mappingRegistry.getMappingsByUrl(lookupPath);
• 最后发现其实和模拟SpringMVC的方式差不多，都是从一张表中取出对应关系。
• 那么这张表是什么时候初始化的呢？初始化的时候就用到了之前学到的Spring的扩展点InitializingBean接口的afterPropertiesSet方法进行表的初始化。（AbstractHandlerMethodMapping）