org.springframework.web.servlet.DispatcherServlet-doDispatch-handle執行介紹

###org.springframework.web.servlet.DispatcherServlet-doDispatch

				/**
				 * 4.預處理,行執行攔截器等
				 */
				if (!mappedHandler.applyPreHandle(processedRequest, response)) {
					return;
				}

				/**
				 * 5.實現執行Controller中(Handler)的方法,返回ModelAndView視圖
				 */
				// Actually invoke the handler.
				mv = ha.handle(processedRequest, response, mappedHandler.getHandler());
				
				if (asyncManager.isConcurrentHandlingStarted()) {
					/**
					 * 判斷 是不是異步請求,是就返回了
					 */
					return;
				}

走了org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter#handle

	public final ModelAndView handle(HttpServletRequest request, HttpServletResponse response, Object handler)
			throws Exception {

		return handleInternal(request, response, (HandlerMethod) handler);
	}

handleInternal方法

org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter#invokeHandlerMethod

	protected ModelAndView invokeHandlerMethod(HttpServletRequest request,
			HttpServletResponse response, HandlerMethod handlerMethod) throws Exception {

		ServletWebRequest webRequest = new ServletWebRequest(request, response);
		try {
			//獲取全局配置的initBinder和當前 Handler-Controller中配置的initBinder用於數據綁定
			WebDataBinderFactory binderFactory = getDataBinderFactory(handlerMethod);
			//獲取所有ModelAttribute&&RequestMapping的方法,在具體的請求之前先執行
			ModelFactory modelFactory = getModelFactory(handlerMethod, binderFactory);
			//將handlerMethod封裝爲ServletInvocableHandlerMethod
			ServletInvocableHandlerMethod invocableMethod = createInvocableHandlerMethod(handlerMethod);
			if (this.argumentResolvers != null) {
				//設置參數解析器
				invocableMethod.setHandlerMethodArgumentResolvers(this.argumentResolvers);
			}
			if (this.returnValueHandlers != null) {
				//設置結果解析器
				invocableMethod.setHandlerMethodReturnValueHandlers(this.returnValueHandlers);
			}
			invocableMethod.setDataBinderFactory(binderFactory);
			invocableMethod.setParameterNameDiscoverer(this.parameterNameDiscoverer);
			//創建 一個ModelAndViewContainer容器
			ModelAndViewContainer mavContainer = new ModelAndViewContainer();
			mavContainer.addAllAttributes(RequestContextUtils.getInputFlashMap(request));
			//調用前的modelFactory中的方法
			modelFactory.initModel(webRequest, mavContainer, invocableMethod);
			//設置是否重定向
			mavContainer.setIgnoreDefaultModelOnRedirect(this.ignoreDefaultModelOnRedirect);
			//設置異常請求
			AsyncWebRequest asyncWebRequest = WebAsyncUtils.createAsyncWebRequest(request, response);
			//異步請求超時時間
			asyncWebRequest.setTimeout(this.asyncRequestTimeout);
			//Web異步管理器
			WebAsyncManager asyncManager = WebAsyncUtils.getAsyncManager(request);
			//設置線程池
			asyncManager.setTaskExecutor(this.taskExecutor);
			asyncManager.setAsyncWebRequest(asyncWebRequest);
			//回調攔截器
			asyncManager.registerCallableInterceptors(this.callableInterceptors);
			asyncManager.registerDeferredResultInterceptors(this.deferredResultInterceptors);

			if (asyncManager.hasConcurrentResult()) {
				Object result = asyncManager.getConcurrentResult();
				mavContainer = (ModelAndViewContainer) asyncManager.getConcurrentResultContext()[0];
				asyncManager.clearConcurrentResult();
				LogFormatUtils.traceDebug(logger, traceOn -> {
					String formatted = LogFormatUtils.formatValue(result, !traceOn);
					return "Resume with async result [" + formatted + "]";
				});
				invocableMethod = invocableMethod.wrapConcurrentResult(result);
			}
			//對請求參數進行處理,調用目標HandlerMethods方法,返回一個ModelAndView
			invocableMethod.invokeAndHandle(webRequest, mavContainer);
			if (asyncManager.isConcurrentHandlingStarted()) {
				//異步處理就直接返回
				return null;
			}
			//返回ModelAndView,同步判斷是否要重定向,還要將flashmanger設置
			return getModelAndView(mavContainer, modelFactory, webRequest);
		}
		finally {
			webRequest.requestCompleted();
		}
	}

org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod#invokeAndHandle

public void invokeAndHandle(ServletWebRequest webRequest, ModelAndViewContainer mavContainer,
			Object... providedArgs) throws Exception {
		//執行請求方法,返回結果
		Object returnValue = invokeForRequest(webRequest, mavContainer, providedArgs);
		//設置返回狀態
		setResponseStatus(webRequest);

		if (returnValue == null) {
			if (isRequestNotModified(webRequest) || getResponseStatus() != null || mavContainer.isRequestHandled()) {
				disableContentCachingIfNecessary(webRequest);
				mavContainer.setRequestHandled(true);
				return;
			}
		}
		else if (StringUtils.hasText(getResponseStatusReason())) {
			mavContainer.setRequestHandled(true);
			return;
		}

		mavContainer.setRequestHandled(false);
		Assert.state(this.returnValueHandlers != null, "No return value handlers");
		try {
			this.returnValueHandlers.handleReturnValue(
					returnValue, getReturnValueType(returnValue), mavContainer, webRequest);
		}
		catch (Exception ex) {
			if (logger.isTraceEnabled()) {
				logger.trace(formatErrorForReturnValue(returnValue), ex);
			}
			throw ex;
		}
	}

org.springframework.web.method.support.InvocableHandlerMethod#invokeForRequest

public Object invokeForRequest(NativeWebRequest request, @Nullable ModelAndViewContainer mavContainer,
			Object... providedArgs) throws Exception {
		//獲取方法的參數集合
		Object[] args = getMethodArgumentValues(request, mavContainer, providedArgs);
		if (logger.isTraceEnabled()) {
			logger.trace("Arguments: " + Arrays.toString(args));
		}
		return doInvoke(args);
	}

org.springframework.web.method.support.InvocableHandlerMethod#getMethodArgumentValues

protected Object[] getMethodArgumentValues(NativeWebRequest request, @Nullable ModelAndViewContainer mavContainer,
			Object... providedArgs) throws Exception {
		//獲取方法所有參數,參數名,參數索引,參數類型,註解等屬性
		MethodParameter[] parameters = getMethodParameters();
		if (ObjectUtils.isEmpty(parameters)) {
			return EMPTY_ARGS;
		}
		//創建一個一樣長度的數組用來綁定參數
		Object[] args = new Object[parameters.length];
		for (int i = 0; i < parameters.length; i++) {
			MethodParameter parameter = parameters[i];
			parameter.initParameterNameDiscovery(this.parameterNameDiscoverer);
			/**
			 * 調用方提供的參數,不是請求時帶來的參數
			 * providedArgs這個東東是空沒有值的
			 */
			args[i] = findProvidedArgument(parameter, providedArgs);
			if (args[i] != null) {
				continue;
			}
			//將參數解析器是否支持
			if (!this.resolvers.supportsParameter(parameter)) {
				throw new IllegalStateException(formatArgumentError(parameter, "No suitable resolver"));
			}
			try {
				//解析參數並綁定
				args[i] = this.resolvers.resolveArgument(parameter, mavContainer, request, this.dataBinderFactory);
			}
			catch (Exception ex) {
				// Leave stack trace for later, exception may actually be resolved and handled...
				if (logger.isDebugEnabled()) {
					String exMsg = ex.getMessage();
					if (exMsg != null && !exMsg.contains(parameter.getExecutable().toGenericString())) {
						logger.debug(formatArgumentError(parameter, exMsg));
					}
				}
				throw ex;
			}
		}
		return args;
	}

org.springframework.web.method.support.HandlerMethodArgumentResolverComposite#resolveArgument

	public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
			NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
		//獲取參數解析器
		HandlerMethodArgumentResolver resolver = getArgumentResolver(parameter);
		if (resolver == null) {
			throw new IllegalArgumentException("Unsupported parameter type [" +
					parameter.getParameterType().getName() + "]. supportsParameter should be called first.");
		}
		//解析參數
		return resolver.resolveArgument(parameter, mavContainer, webRequest, binderFactory);
	}

org.springframework.web.method.annotation.AbstractNamedValueMethodArgumentResolver#resolveArgument

	public Object resolveArgument(MethodParameter parameter, @Nullable ModelAndViewContainer mavContainer,
			NativeWebRequest webRequest, @Nullable WebDataBinderFactory binderFactory) throws Exception {
		//獲取參數解析器
		HandlerMethodArgumentResolver resolver = getArgumentResolver(parameter);
		if (resolver == null) {
			throw new IllegalArgumentException("Unsupported parameter type [" +
					parameter.getParameterType().getName() + "]. supportsParameter should be called first.");
		}
		//解析參數
		return resolver.resolveArgument(parameter, mavContainer, webRequest, binderFactory);
	}

org.springframework.web.method.annotation.RequestParamMethodArgumentResolver#resolveName

protected Object resolveName(String name, MethodParameter parameter, NativeWebRequest request) throws Exception {
		HttpServletRequest servletRequest = request.getNativeRequest(HttpServletRequest.class);

		if (servletRequest != null) {
			Object mpArg = MultipartResolutionDelegate.resolveMultipartArgument(name, parameter, servletRequest);
			if (mpArg != MultipartResolutionDelegate.UNRESOLVABLE) {
				return mpArg;
			}
		}

		Object arg = null;
		MultipartRequest multipartRequest = request.getNativeRequest(MultipartRequest.class);
		if (multipartRequest != null) {
			List<MultipartFile> files = multipartRequest.getFiles(name);
			if (!files.isEmpty()) {
				arg = (files.size() == 1 ? files.get(0) : files);
			}
		}
		if (arg == null) { 
			//從請求去拿出參數
			String[] paramValues = request.getParameterValues(name);
			if (paramValues != null) {
				arg = (paramValues.length == 1 ? paramValues[0] : paramValues);
			}
		}
		return arg;
	}

org.springframework.web.method.support.InvocableHandlerMethod#doInvoke方法

@Nullable
	protected Object doInvoke(Object... args) throws Exception {
		//獲取方法並授權method.setAccessible(true);
		ReflectionUtils.makeAccessible(getBridgedMethod());
		try {
			//反射調用
			return getBridgedMethod().invoke(getBean(), args);

		}