springMVC HandlerExecutionChain处理器执行链Handler和Interceptor详情

最新推荐文章于 2025-06-21 09:00:00 发布

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最新推荐文章于 2025-06-21 09:00:00 发布 · 3.5k 阅读

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本文介绍了SpringMVC的工作流程，从web.xml的DispatcherServlet配置开始，详细阐述HandlerMapping如何将请求映射为HandlerExecutionChain，然后通过HandlerAdapter调用处理方法生成ModelAndView，接着ViewResolver解析视图并返回给用户。重点分析了DispaterServlet中的doDispatch方法和HandlerExecutionChain在处理请求过程中的作用，揭示了HandlerMapping与HandlerExecutionChain的紧密关系。

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简介springMVC的工作流程：
在web.xml中部署DispaterServlet，并配置springmvc.xml等文件;
将映射文件请求到处理器HandlerMapping;
HandlerMapping会把请求映射为HandlerExecutionChain类型的handler对象;
将handler对象作为参数传递给HandlerAdapter的实例化对象，调用其handler方法会生成一个ModelAndView对象;
通过ViewResolver视图解析器，将上一步骤中生成的ModelAndView解析为View;
DispatcherServlet根据获取到View，将视图返回给用户。
（一）DispaterServlet简单分析

protected void doDispatch(HttpServletRequest request, HttpServletResponse response) throws Exception {
		HttpServletRequest processedRequest = request;
		//**处理器执行链由处理器对象和拦截器组成。（特别注意 拦截器相关执行都在此类中执行）**
		HandlerExecutionChain mappedHandler = null;
		boolean multipartRequestParsed = false;

		WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);

		try {
			ModelAndView mv = null;
			Exception dispatchException = null;

			try {
				processedRequest = checkMultipart(request);
				multipartRequestParsed = (processedRequest != request);

				// Determine handler for the current request. 获取请求的处理器
				mappedHandler = getHandler(processedRequest);
				if (mappedHandler == null || mappedHandler.getHandler() == null) {
					noHandlerFound(processedRequest, response);
					return;
				}

				// Determine handler adapter for the current request.
				HandlerAdapter ha = getHandlerAdapter(mappedHandler.getHandler());

				// Process last-modified header, if supported by the handler.
				String method = request.getMethod();
				boolean isGet = "GET".equals(method);
				if (isGe