JavaaWeb中对request,session,application的理解

注意！

无论是request,session,application必须先调用setAttribute得到保存作用域中保存数据

request：一次请求响应范围

@WebServlet("/demo01")
public class Demo01Servlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setAttribute("uname","request保存作用域");
        request.getRequestDispatcher("demo02").forward(request,response);
    }
}