Untitled

import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;

/**
 * Created by Artur on 11.12.2016.
 */
public class AuthFilter implements Filter {
    private List<String> pathFilter= Arrays.asList(new String[]{"add","welcome"});
    public AuthFilter(){}
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain) throws IOException, ServletException {
        String uri=((HttpServletRequest)request).getRequestURI();
        String path=uri.substring(uri.lastIndexOf("/"));
        if (pathFilter.contains(path)){filterChain.doFilter(request,response);
        return;
        }
        HttpSession session=((HttpServletRequest)request).getSession();
        User user=(User)session.getAttribute("PRINCIPAL");
        if (user!=null){filterChain.doFilter(request,response);
        return;
        }
        ((HttpServletResponse)response).sendRedirect("login.jsp?login=invalid");

    }

    public void destroy() {

    }
}

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">
    <servlet>
        <servlet-name>welcome</servlet-name>
        <servlet-class>HomeServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>welcome</servlet-name>
        <url-pattern>/welcome</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>login</servlet-name>
        <servlet-class>LoginServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>login</servlet-name>
        <url-pattern>/login</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>sign-up</servlet-name>
        <servlet-class>checkin</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>sign-up</servlet-name>
        <url-pattern>/sign-up</url-pattern>
    </servlet-mapping>
    <servlet>
        <servlet-name>logout</servlet-name>
        <servlet-class>LogoutServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>logout</servlet-name>
        <url-pattern>/logout</url-pattern>
    </servlet-mapping>
    <filter>
        <filter-name>authFilter</filter-name>
        <filter-class>AuthFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>authFilter</filter-name>
        <url-pattern>/**</url-pattern>
    </filter-mapping>
</web-app>


<%--
  Created by IntelliJ IDEA.
  User: Artur
  Date: 11.12.2016
  Time: 14:33
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
${day} ${user}

<button>выйти</button>
</body>
</html>

</body>
</html>

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

/**
 * Created by Artur on 11.12.2016.
 */
public class LoginServlet extends HttpServlet {
    private  Datasource userDatasource;
    public LoginServlet(){
        userDatasource=new Datasource();
    }
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        HttpSession session=req.getSession();
        String username = req.getParameter("username");
        String password = req.getParameter("password");

        if(username!=null&&password!=null) {
         User user = userDatasource.getByUsernameAndPassword(username, password);
            System.out.println(user.getUsername());
            System.out.println(user.getPassword());
            if (user != null) {
                session.setAttribute("PRINCIPAL", user);
                resp.sendRedirect("/welcome");
                return;
            }
        }
        resp.sendRedirect("login.jsp?loginopassword=invalid");
    }
}

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
/**
 * Created by Artur on 11.12.2016.
 */
public class HomeServlet extends HttpServlet {

        @Override
        protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
            HttpSession session=req.getSession();
            session.setAttribute("",2345);
            TimeDay objectTime=new TimeDay();
            String time=objectTime.getTime();
            req.setAttribute("day",time);
            Object userObject=session.getAttribute("PRINCIPAL");
            User user=(User)userObject;

            System.out.println(user.getFirstname());
            req.setAttribute("user",user.getFirstname());
            RequestDispatcher requestDispatcher=getServletContext().getRequestDispatcher("/home.jsp");
            requestDispatcher.forward(req,resp);
        }

    }