新・Servlet/JSP入門編4: MVCモデルについて学習しよう

package jp.paiza.model;

public class LoginModel {
    
    public boolean login(String userId, String password) {
        return "kyoko".equals(userId) && "paiza".equals(password);
    }
}

package jp.paiza.servlet;

import java.io.*;
import jakarta.servlet.*;
import jakarta.servlet.annotation.*;
import jakarta.servlet.http.*;
import jp.paiza.model.*;

@WebServlet("/login")
public class LoginServlet extends HttpServlet {
            
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse res) 
        throws ServletException, IOException {
        
        RequestDispatcher d = 
            req.getRequestDispatcher("/WEB-INF/jsp/login-input.jsp");
        
        d.forward(req, res);
    }
    
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse res) 
        throws ServletException, IOException {
        
        req.setCharacterEncoding("UTF-8");

        String userId = req.getParameter("user-id");
        String password = req.getParameter("password");

        LoginModel m = new LoginModel();
        
        if (m.login(userId, password)) {
            RequestDispatcher d = 
                req.getRequestDispatcher("/WEB-INF/jsp/login-result.jsp");
            d.forward(req, res);
        } else {
            res.sendRedirect("login");
        }
    }
}