mv = ha.handle(processedRequest, response, mappedHandler.getHandler());//945行返回了 ModelAndView 对象

processDispatchResult(processedRequest, response, mappedHandler, mv, dispatchException);// 959行进行的就是返回值处理问题

render(mv, request, response); //1012进行视图的渲染（包含视图解析）

protected void render(ModelAndView mv, HttpServletRequest request, HttpServletResponse response) throws Exception {// Determine locale for request and apply it to the response.Locale locale = this.localeResolver.resolveLocale(request);response.setLocale(locale);View view;if (mv.isReference()) {// We need to resolve the view name.view = resolveViewName(mv.getViewName(), mv.getModelInternal(), locale, request);if (view == null) {throw new ServletException("Could not resolve view with name '" + mv.getViewName() + "' in servlet with name '" +getServletName() + "'");}}else {// No need to lookup: the ModelAndView object contains the actual View object.view = mv.getView();if (view == null) {throw new ServletException("ModelAndView [" + mv + "] neither contains a view name nor a " +"View object in servlet with name '" + getServletName() + "'");}}// Delegate to the View object for rendering.if (logger.isDebugEnabled()) {logger.debug("Rendering view [" + view + "] in DispatcherServlet with name '" + getServletName() + "'");}try {view.render(mv.getModelInternal(), request, response);}catch (Exception ex) {if (logger.isDebugEnabled()) {logger.debug("Error rendering view [" + view + "] in DispatcherServlet with name '"+ getServletName() + "'", ex);}throw ex;}}

protected View resolveViewName(String viewName, Map<String, Object> model, Locale locale,HttpServletRequest request) throws Exception {　　for (ViewResolver viewResolver : this.viewResolvers) {View view = viewResolver.resolveViewName(viewName, locale);
　　　　if (view != null) {
　　　　　　return view;}}
　　return null;
}

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
　　<property name="prefix" value="/WEB-INF/views/"/>
　　<property name="suffix" value=".jsp"/>
</bean>

<bean class="org.springframework.web.servlet.view.BeanNameViewResolver">
　　<property name="order" value="99"/>
</bean><bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
　　<property name="prefix" value="/WEB-INF/views/"/>
　　<property name="suffix" value=".jsp"/>
　　<property name="order" value="-99"/>
</bean>

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
　　<property name="prefix" value="/WEB-INF/views/"/>
　　<property name="suffix" value=".jsp"/>
</bean><bean class="org.springframework.web.servlet.view.BeanNameViewResolver">
</bean>

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
　　<property name="prefix" value="/WEB-INF/views/"/>
　　<property name="suffix" value=".jsp"/>
</bean><bean class="org.springframework.web.servlet.view.BeanNameViewResolver">
</bean>

<bean class="org.springframework.web.servlet.view.BeanNameViewResolver">
</bean><bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
　　<property name="prefix" value="/WEB-INF/views/"/>
　　<property name="suffix" value=".jsp"/>
</bean>

@Override
public View resolveViewName(String viewName, Locale locale) throws Exception {if (!isCache()) {
　　　　return createView(viewName, locale);}
　　else {Object cacheKey = getCacheKey(viewName, locale);View view = this.viewAccessCache.get(cacheKey);
　　　　if (view == null) {
　　　　　　synchronized (this.viewCreationCache) {view = this.viewCreationCache.get(cacheKey);
　　　　　　if (view == null) {
　　　　　　　　// Ask the subclass to create the View object.view = createView(viewName, locale);
　　　　　　　　if (view == null && this.cacheUnresolved) {view = UNRESOLVED_VIEW;}
　　　　　　　　if (view != null) {
　　　　　　　　　　this.viewAccessCache.put(cacheKey, view);
　　　　　　　　　　this.viewCreationCache.put(cacheKey, view);
　　　　　　　　　　if (logger.isTraceEnabled()) {logger.trace("Cached view [" + cacheKey + "]");}}}}}
　　return (view != UNRESOLVED_VIEW ? view : null);}
}

protected View createView(String viewName, Locale locale) throws Exception {// If this resolver is not supposed to handle the given view,// return null to pass on to the next resolver in the chain.if (!canHandle(viewName, locale)) {return null;}// Check for special "redirect:" prefix.if (viewName.startsWith(REDIRECT_URL_PREFIX)) {String redirectUrl = viewName.substring(REDIRECT_URL_PREFIX.length());RedirectView view = new RedirectView(redirectUrl, isRedirectContextRelative(), isRedirectHttp10Compatible());return applyLifecycleMethods(viewName, view);}// Check for special "forward:" prefix.if (viewName.startsWith(FORWARD_URL_PREFIX)) {String forwardUrl = viewName.substring(FORWARD_URL_PREFIX.length());return new InternalResourceView(forwardUrl);}// Else fall back to superclass implementation: calling loadView.
　　return super.createView(viewName, locale);
}    

AbstractUrlBasedView view = buildView(viewName);
View result = applyLifecycleMethods(viewName, view);
return (view.checkResource(locale) ? result : null);

protected AbstractUrlBasedView buildView(String viewName) throws Exception {AbstractUrlBasedView view = (AbstractUrlBasedView) BeanUtils.instantiateClass(getViewClass());view.setUrl(getPrefix() + viewName + getSuffix());String contentType = getContentType();
　　if (contentType != null) {view.setContentType(contentType);}view.setRequestContextAttribute(getRequestContextAttribute());view.setAttributesMap(getAttributesMap());
　　if (this.exposePathVariables != null) {view.setExposePathVariables(exposePathVariables);}
　　return view;
}

public View resolveViewName(String viewName, Locale locale) throws BeansException {ApplicationContext context = getApplicationContext();if (!context.containsBean(viewName)) {// Allow for ViewResolver chaining.return null;}return context.getBean(viewName, View.class);
}    

public <T> T getBean(String name, Class<T> requiredType) throws BeansException {this.assertBeanFactoryActive();return this.getBeanFactory().getBean(name, requiredType);
}

public void render(Map<String, ?> model, HttpServletRequest request, HttpServletResponse response) throws Exception {
　　if (logger.isTraceEnabled()) {logger.trace("Rendering view with name '" + this.beanName + "' with model " + model +" and static attributes " + this.staticAttributes);}Map<String, Object> mergedModel = createMergedOutputModel(model, request, response);prepareResponse(request, response);renderMergedOutputModel(mergedModel, request, response);
}

@Override
protected void renderMergedOutputModel(Map<String, Object> model, HttpServletRequest request, HttpServletResponse response) throws Exception {　　// Determine which request handle to expose to the RequestDispatcher.HttpServletRequest requestToExpose = getRequestToExpose(request);　　// Expose the model object as request attributes.
　　exposeModelAsRequestAttributes(model, requestToExpose);// Expose helpers as request attributes, if any.
　　exposeHelpers(requestToExpose);　　// Determine the path for the request dispatcher.String dispatcherPath = prepareForRendering(requestToExpose, response);　　// Obtain a RequestDispatcher for the target resource (typically a JSP).RequestDispatcher rd = getRequestDispatcher(requestToExpose, dispatcherPath);
　　if (rd == null) {throw new ServletException("Could not get RequestDispatcher for [" + getUrl() +"]: Check that the corresponding file exists within your web application archive!");}　　// If already included or response already committed, perform include, else forward.
　　if (useInclude(requestToExpose, response)) {response.setContentType(getContentType());if (logger.isDebugEnabled()) {logger.debug("Including resource [" + getUrl() + "] in InternalResourceView '" + getBeanName() + "'");}rd.include(requestToExpose, response);}else {// Note: The forwarded resource is supposed to determine the content type itself.if (logger.isDebugEnabled()) {logger.debug("Forwarding to resource [" + getUrl() + "] in InternalResourceView '" + getBeanName() + "'");}rd.forward(requestToExpose, response);}
}