Error HTTP Status 500 - javax.servlet.ServletException: Error instantiating servlet class ?

[Raf Beni]

I have problem with this code!

I want to have a simple dynamic web with CRUD function. It's folder of code



UserController.java

package com.daniel.controller;

import java.io.IOException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.daniel.dao.UserDao;
import com.daniel.model.User;

public class UserController {
	private static final long serialVersionUID = 1L;
    private static String INSERT_OR_EDIT = "/user.jsp";
    private static String LIST_USER = "/listUser.jsp";
    private UserDao dao;

    public UserController() {
        super();
        dao = new UserDao();
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String forward="";
        String action = request.getParameter("action");

        if (action.equalsIgnoreCase("delete")){
            int userId = Integer.parseInt(request.getParameter("userId"));
            dao.deleteUser(userId);
            forward = LIST_USER;
            request.setAttribute("users", dao.getAllUsers());    
        } else if (action.equalsIgnoreCase("edit")){
            forward = INSERT_OR_EDIT;
            int userId = Integer.parseInt(request.getParameter("userId"));
            User user = dao.getUserById(userId);
            request.setAttribute("user", user);
        } else if (action.equalsIgnoreCase("listUser")){
            forward = LIST_USER;
            request.setAttribute("users", dao.getAllUsers());
        } else {
            forward = INSERT_OR_EDIT;
        }

        RequestDispatcher view = request.getRequestDispatcher(forward);
        view.forward(request, response);
    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        User user = new User();
        user.setFirstName(request.getParameter("firstName"));
        user.setLastName(request.getParameter("lastName"));
        try {
            Date dob = new SimpleDateFormat("MM/dd/yyyy").parse(request.getParameter("dob"));
            user.setDob(dob);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        user.setEmail(request.getParameter("email"));
        String userid = request.getParameter("userid");
        if(userid == null || userid.isEmpty())
        {
            dao.addUser(user);
        }
        else
        {
            user.setUserid(Integer.parseInt(userid));
            dao.updateUser(user);
        }
        RequestDispatcher view = request.getRequestDispatcher(LIST_USER);
        request.setAttribute("users", dao.getAllUsers());
        view.forward(request, response);
    }
}

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" id="WebApp_ID" version="2.5">
  <display-name>SimpleJspServletDB</display-name>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
    <description></description>
    <display-name>UserController</display-name>
    <servlet-name>UserController</servlet-name>
    <servlet-class>com.daniel.controller.UserController</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>UserController</servlet-name>
    <url-pattern>/UserController</url-pattern>
  </servlet-mapping>
</web-app>

When I build project, it has problem :


So, how i fix it? Help me, please

[Joe San]

Your UserController is not a Servlet. Does that give you a hint?