Question

我想验证有关用户的信息。如果已输入用户并尝试进入/login页面，请转到用户页面。

到目前为止，我有这个：

StartServlet

public class StartServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        UserDTO userDTO = (UserDTO) req.getSession().getAttribute("userDTO");
        if (userDTO == null) {
            req.getRequestDispatcher(req.getContextPath() + "/WEB-INF/pages/login.jspx").forward(req, resp);
        } else {
            req.getRequestDispatcher(req.getContextPath() + "/checklogin").forward(req, resp);
        }
    }
}

ValidateServlet

public class ValidateServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String email = req.getParameter("email");
        String password = req.getParameter("password");
        UserDTO userDTO = (UserDTO) req.getSession().getAttribute("userDTO");

        if (userDTO == null) {
            userDTO = UserService.getInstance().validateUserDTO(email, password);
        }

        if (userDTO != null) {
            req.getSession().setAttribute("userDTO", userDTO);
            if (userDTO.getRole() == Role.ADMINISTRATOR || userDTO.getRole() == Role.SUPERADMINISTRATOR) {
                req.getRequestDispatcher(req.getContextPath() + "/admin/catalog").forward(req, resp);
            } else {
                req.getRequestDispatcher(req.getContextPath() + "/WEB-INF/pages/user/catalog/catalog.jspx").forward(req, resp);
            }
        } else {
            String errorMsg = "Email or password is incorrect";
            req.setAttribute("error", errorMsg);
            req.getRequestDispatcher(req.getContextPath() + "/WEB-INF/pages/login.jspx").forward(req, resp);
        }
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }
}

AdminCatalogServlet

public class AdminCatalogServlet extends HttpServlet {

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        List<ItemDTO> itemsDTO = ItemService.getInstance().getAllItemsDTO();
        req.setAttribute("itemsDTO", itemsDTO);
        req.getRequestDispatcher(req.getContextPath() + "/WEB-INF/pages/admin/catalog/catalog.jspx").forward(req, resp);
    }

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        doPost(req, resp);
    }
}

的web.xml

<servlet>
        <servlet-name>StartServlet</servlet-name>
        <servlet-class>...StartServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>StartServlet</servlet-name>
        <url-pattern>/</url-pattern>
        <url-pattern>/login</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>ValidateServlet</servlet-name>
        <servlet-class>...ValidateServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>ValidateServlet</servlet-name>
        <url-pattern>/checklogin</url-pattern>
    </servlet-mapping>
<servlet>
        <servlet-name>AdminCatalogServlet</servlet-name>
        <servlet-class>...AdminCatalogServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>AdminCatalogServlet</servlet-name>
        <url-pattern>/admin/catalog</url-pattern>
    </servlet-mapping>

问题：我们从StartServlet开始，在致电/或/login时。然后我们输入login，password to form（method = POST）并提交给ValidateServlet。

之后我们转发到AdminCatalogServlet（来自Admin的前瞻性）。然后我们转发到jsp，我们的浏览器显示给我们页面。（这是对数据库的2个请求）用户和项目。我想，就是这样，但是......然后tomcat再次在doGet()中运行方法StartServlet，将用户从会话中转移到ValidateServlet转到方法Get。并反复向数据库请求项目。

为什么会这样？感谢。

更新：如果从ValidateServlet或AdminCatalogServlet删除了doGet（）方法，则问题就会消失，但在尝试输入{时却无法工作登录后{1}}。

UPDATE2：我已按照评论中的建议进行追踪（可能不对）。首先是第一个请求（/login），然后是引导程序的附加数据集。最后，使用POST方法在/validate上发出第二个请求。

UPDATE2：要解决此问题，我已将GET映射从StartServlet更改为/。这意味着对""的任何请求都将被重定向到此servlet。问题是由于自从Bootstrap连接后，浏览器还向host:port/发送了对favicon，css等的请求。由于host:port/favicon已映射到StartServlet，因此它已收到此请求，方法/已启动。有关详细信息，请参阅Tomcat中的GET

在结束方法之后，doPost（）运行方法doGet（）而不在StartServlet中调用此方法

0 个答案: