HTTP 404 未找到 EJB Servlet

如何解决HTTP 404 未找到 EJB Servlet

您好，我正在处理一些 EJB 项目并遇到了这个问题。每次当我尝试在我的 servlet 中插入代码 > 调用企业 bean > UserFacade 时，它​​都会返回 HTTP 404 - Not Found。如果我评论那些导入的行，它会正常工作。这个问题有什么解决办法吗？

package controller;

import java.io.IOException;
import java.io.PrintWriter;
import javax.ejb.EJB;
import javax.servlet.servletexception;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import model.UserFacade;

/**
 *
 * @author sherw
 */
@WebServlet(name = "Login",urlPatterns = {"/Login"})
public class Login extends HttpServlet {

    @EJB //Imported Code
    private UserFacade userFacade; //Imported Code

    protected void processRequest(HttpServletRequest request,HttpServletResponse response)
            throws servletexception,IOException {
        response.setContentType("text/html;charset=UTF-8");
        try (PrintWriter out = response.getWriter()) {

        }
    }

    // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code.">

    @Override
    protected void doGet(HttpServletRequest request,IOException {
        processRequest(request,response);
    }

    @Override
    protected void doPost(HttpServletRequest request,response);
    }

    @Override
    public String getServletInfo() {
        return "Short description";
    }// </editor-fold>

}