java - 使用tomcat登录后将请求从servlet转发到jsp

Question

我正在尝试使用 tomacat 登录后将请求转发到 jsp 文件。但它(servlet)不转发请求。谁能找出这里的错误？

小服务程序:

public class AuthenticationServer extends HttpServlet {

    public void doPost (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doService(request, response);
    }

    public void doGet (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        doService (request, response);
    }

    public void doService (HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String user = request.getRemoteUser();
        request.setAttribute("user", user);
        RequestDispatcher dispatcher = request.getRequestDispatcher("/" + request.getParameter("direct"));
        dispatcher.forward(request, response);
    }
}

当我打印 "/"+ request.getParameter("direct") 时，它会打印出 /welcome.jsp。但它只是不转发它。

Answer 1

request.getRequestDispatcher(String path);

指定的路径可以是相对的，尽管它不能扩展到当前 servlet 上下文之外。如果路径以 "/" 开头，则它被解释为相对于当前上下文根。如果 servlet 容器无法返回 RequestDispatcher，此方法也会返回 null。试试这个:RequestDispatcher dispatcher = request.getRequestDispatcher(request.getParameter("direct"));