AuthorizationServlet

package com.computerScience.servlets;

import com.computerScience.addition.MD5;
import com.computerScience.dto.UserDTO;
import com.computerScience.service.impl.UserServiceImpl;
import com.computerScience.util.EntityConstants;
import com.computerScience.util.View;

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 javax.servlet.http.HttpSession;
import java.io.IOException;
import java.util.List;

/**
 * Created by Sky_el on 01.06.2017.
 */
@WebServlet(View.Mapping.LOGIN)
public class AuthorizationServlet extends HttpServlet {
    private final MD5 md5 = new MD5();
    private final UserServiceImpl userService = new UserServiceImpl();

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String login = req.getParameter(EntityConstants.EMAIL_PARAM);
        String password = req.getParameter(EntityConstants.PASSWORD_PARAM);

        List<UserDTO> userList = userService.getUsersList();
        UserDTO foundUser;

        if((foundUser = searchInAccountList(userList, login, md5.md5Custom(password))) != null) {
            HttpSession session = req.getSession();
            session.setAttribute(EntityConstants.USER_SESSION_ATTR, foundUser);
            resp.sendRedirect(String.format("%s%s", req.getContextPath(), View.Mapping.MAIN_PAGE));
        }
        else
        {
            req.setAttribute(EntityConstants.NOT_FOUND_ERROR_ATTR, true);
            req.getRequestDispatcher(View.MAIN_JSP).forward(req, resp); // СДЕЛАТЬ РЕДИРЕКТ НА СТРАНИЦУ, ОТ КУДА БЫЛ ВЫПОЛНЕН ЗАПРОС
        }
    }

    private UserDTO searchInAccountList(List<UserDTO> userList, String email, String password) {
        for(UserDTO user : userList) {
            if(user.getEmail().equals(email) && user.getPassword().equals(password))
                return user;
        }
        return null;
    }
}