@Override protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { String id = req.getParameter("id"); String password = req.getParameter("password"); if (id == null || id.length() == 0 || password == null || password.length() == 0) { resp.sendError(400, "incomplete parameter"); return; } AccountService service = (AccountService) context.getBean("accountService"); try { service.login(id, password); resp.getWriter().print("Login Successful!"); } catch (AccountServiceException e) { resp.sendError(400, e.getMessage()); } }