总结：

ViewResolver 如果要改需要自己注入到容器中并进行修改， springmvc使用的是InterResourceViewResover
view不需要自己改，是springmvc根据return返回值选的

既然看到有ModelAndView直接跳转jsp的， 有请求转发的，有重定向的，这里整体是怎么设计的： (@ResponseBody的在此不作展开)

HiController:

@Controllerpublic class HiController { @RequestMapping("/hi") public ModelAndView getHi() { ModelAndView mav = new ModelAndView("me"); return mav; } @RequestMapping("/yes") public String forwardYes() { return "forward:patch"; } @RequestMapping("/no") public String RedirectNo() { return "redirect:patch"; } @ResponseBody @RequestMapping("/patch") public String redirectNo() { return "from forward or redirect request"; // 这种情况没有view，在这里不讨论 }}

主要代码：

DispatcherServlet.doDispatch(）里的：

DispatcherServlet.render方法：

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 != null ? this.localeResolver.resolveLocale(request) : request.getLocale()); response.setLocale(locale); View view; String viewName = mv.getViewName(); if (viewName != null) { // We need to resolve the view name. view = resolveViewName(viewName, mv.getModelInternal(), locale, request); // 1 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.isTraceEnabled()) { logger.trace("Rendering view [" + view + "] "); } try { if (mv.getStatus() != null) { response.setStatus(mv.getStatus().value()); } view.render(mv.getModelInternal(), request, response); // 2 } catch (Exception ex) { if (logger.isDebugEnabled()) { logger.debug("Error rendering view [" + view + "]", ex); } throw ex; } }

1. view = resolveViewName()会根据不同的路径生成不同的view, return mav 会返回JstlView, return "forward:/patch" 会返回InternalResourceView， return "direct:/patch" 会返回IndirectView

2. 不同的view去走不同的view.render()， 根据不同的view重写abstract void renderMergedOutputModel方法

再来看是如何生成不同的view:[/code][code]view = resolveViewName() 进去，走到
DiapatcherServlet先有ViewResolver这个，用来生成不同的view

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

ViewResolver 接口只有一个方法

public interface ViewResolver { @Nullable View resolveViewName(String viewName, Locale locale) throws Exception;}

要配置具体的视图解析器，springMVC中使用的是InterResourceViewResover，InterResourceViewResover 和他的父类UrlBasedViewResolver中都没有重写resolveViewName方法，再上一层的父类AbstractCahingViewResolver实现了resolveViewName方法

AbstractCahingViewResolver：

@Override @Nullable 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.cacheFilter.filter(view, viewName, locale)) { this.viewAccessCache.put(cacheKey, view); this.viewCreationCache.put(cacheKey, view); } } } } else { if (logger.isTraceEnabled()) { logger.trace(formatKey(cacheKey) + "served from cache"); } } return (view != UNRESOLVED_VIEW ? view : null); } }

InterResourceViewResover中没有createView方法，所以是调用它父类UrlBasedViewResolver的createView方法：

@Override 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()); String[] hosts = getRedirectHosts(); if (hosts != null) { view.setHosts(hosts); } return applyLifecycleMethods(REDIRECT_URL_PREFIX, view); // return "direct:/patch"在这里构造view } // Check for special "forward:" prefix. if (viewName.startsWith(FORWARD_URL_PREFIX)) { String forwardUrl = viewName.substring(FORWARD_URL_PREFIX.length()); InternalResourceView view = new InternalResourceView(forwardUrl); return applyLifecycleMethods(FORWARD_URL_PREFIX, view); // return "forward:/patch" 在这里构造view } // Else fall back to superclass implementation: calling loadView. return super.createView(viewName, locale); // return mav 在这里构造view }

关于ViewResolver的代码执行顺序， 前面分析那么多，这里再打断点快速验证一下：

进DispatcherServlet的doDispatch看到就是这个解析器：

断点放在这里，

然后下一步：

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。