一，示例
1，在handler类中添加方法如下：

//重定向
    @RequestMapping("/testRedirect")
    public String testRedirect() {
        System.out.println("testRedirect");
        return "redirect:/index.jsp";
    }

二，源码解析
1，进入DispatcherServlet的doDispatch方法
2，找到视图mv
mv = ha.handle(processedRequest, response, mappedHandler.getHandler());
3，进入processDispatchResult方法
processDispatchResult(processedRequest, response, mappedHandler, mv, dispatchException);
4，进入渲染视图 方法为render
render(mv, request, response);
5，进入解析视图 方法为resolveViewName
view = resolveViewName(mv.getViewName(), mv.getModelInternal(), locale, request);
6，再进入如下代码中的resolveViewName，是一个接口
View view = viewResolver.resolveViewName(viewName, locale);
7，找到resolveViewName接口的实现类AbstractCachingViewResolver
8，进入创建视图 createView方法 是一个抽象类，找到他的继承子类UrlBasedViewResolver
return createView(viewName, locale);
9，createView的继承子类UrlBasedViewResolver分析
在UrlBasedViewResolver的createView方法中可以看到如下代码

//如果返回名字是以redirect开头就返回一个redirect视图，如果返回名字以forWord开头就返回InternalResourceView视图
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);
        }