protected void Register(HttpServletRequest request, HttpServletResponse response)
      throws ServletException, IOException {

    String username = request.getParameter("username");
    String password1 = request.getParameter("password1");
    String password2 = request.getParameter("password2");
    String email = request.getParameter("email");

    if (username == null
        || password1 == null
        || password2 == null
        || !password1.equals(password2)) {
      response.sendRedirect("register.jsp");
      return;
    }

    UserBean userBean = new UserBean();
    boolean isExist = userBean.isExist(username);
    if (!isExist) {
      userBean.add(username, password1, email);
      response.sendRedirect("login.jsp");
      return;
    } else {
      response.sendRedirect("register.jsp");
      return;
    }
  }