JSP的两种跳转方式分别是什么，有何区别
1、带request参数的跳转?? request.setAttribute("par", "val");?? request.getRequestDispatcher("a.jsp").forward(request, response);?? 在目的页面可以获取参数?? String?val = request.getAttribute("par")==null?:(String)request.getAttribute("par");2、不带request参数的跳转?? response.sendredirect("a.jsp");