SpringMVC请求处理方法参数类型及返回类型

SpringMVC请求处理方法可出现的参数类型
    如果需要访问HttpServletRequest对象，则可以添加HttpServletRequest作为参数，Spring会将对象传递给方法：
        @RequestMapping(value="/login")
        public String login(HttpServletRequest request){
            return "login";
        }
    如果需要访问HttpSession对象，则可以添加HttpSession作为参数，Spring会将对象传递给方法：
        @RequestMapping(value="/login")
        public String login(HttpSession session){
            return "login";
        }
    以下可以在请求处理方法中出现的参数类型：
        javax.servlet.ServletRequest或javax.servlet.http.HttpServletRequest
        javax.servlet.ServletResponse或java.servlet.http.HttpServletResponse
        javax.servlet.http.HttpSession
        org.springframework.web.context.request.WebRequest或org.springframework.web.context.request.NativeWebRequest
        java.util.Locale
        java.io.InputStream或java.io.Reader
        java.io.OutputStream或java.io.Writer
        java.security.Principal
        HttpEntity<?>
        java.util.Map
        org.springframework.ui.Model
        org.springframework.ui.ModelMap
        org.springframework.web.servlet.mvc.support.RedirectAttributes
        org.springframework.validation.Errors
        org.springframework.validation.BindingResult
        org.springframework.web.bind.support.SessionStatus
        org.springframework.web.util.UriComponentsBuilder
        @PathVariable、@@MatrixVariable注解
        @RequestParam、@RequestHeader、@RequestBody、@RequestPart注解
       
SpringMVC请求处理方法可返回的类型
    org.springframework.web.portlet.ModelAndView
    org.springframework.ui.Model
    java.util.Map<k,v>
    org.springframework.web.servlet.View
    java.lang.String
    HttpEntity或ResponseEntity
    java.util.concurrent.Callable
    org.springframework.web.context.request.async.DeferredResult
    void