We can bind the objects on HttpSession instance and get the objects by using setAttribute and getAttribute methods.

In the previous page, we have learnt about what is HttpSession, How to store and get data from session object etc.

Here, we are going to create a real world login and logout application without using database code. We are assuming that password is admin123.

Visit here for login and logout application using cookies only servlet login and logout example using cookies

In this example, we are creating 3 links: login, logout and profile. User can’t go to profile page until he/she is logged in. If user is logged out, he need to login again to visit profile.

In this application, we have created following files.

1. index.html
2. link.html
3. login.html
4. LoginServlet.java
5. LogoutServlet.java
6. ProfileServlet.java
7. web.xml

File: index.html

  
  
  
  
Servlet Login Example

Login App using HttpSession

Login|
Logout|
Profile

File: link.html

Login |  
Logout |  
Profile

File: login.html

File: LoginServlet.java

import java.io.IOException;  
import java.io.PrintWriter;  
  
import javax.servlet.ServletException;  
import javax.servlet.http.HttpServlet;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
import javax.servlet.http.HttpSession;  
public class LoginServlet extends HttpServlet {  
    protected void doPost(HttpServletRequest request, HttpServletResponse response)  
                    throws ServletException, IOException {  
        response.setContentType("text/html");  
        PrintWriter out=response.getWriter();  
        request.getRequestDispatcher("link.html").include(request, response);  
          
        String name=request.getParameter("name");  
        String password=request.getParameter("password");  
          
        if(password.equals("admin123")){  
        out.print("Welcome, "+name);  
        HttpSession session=request.getSession();  
        session.setAttribute("name",name);  
        }  
        else{  
            out.print("Sorry, username or password error!");  
            request.getRequestDispatcher("login.html").include(request, response);  
        }  
        out.close();  
    }  
}

File: LogoutServlet.java

import java.io.IOException;  
import java.io.PrintWriter;  
  
import javax.servlet.ServletException;  
import javax.servlet.http.HttpServlet;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
import javax.servlet.http.HttpSession;  
public class LogoutServlet extends HttpServlet {  
        protected void doGet(HttpServletRequest request, HttpServletResponse response)  
                                throws ServletException, IOException {  
            response.setContentType("text/html");  
            PrintWriter out=response.getWriter();  
              
            request.getRequestDispatcher("link.html").include(request, response);  
              
            HttpSession session=request.getSession();  
            session.invalidate();  
              
            out.print("You are successfully logged out!");  
              
            out.close();  
    }  
}

File: ProfileServlet.java

import java.io.IOException;  
import java.io.PrintWriter;  
import javax.servlet.ServletException;  
import javax.servlet.http.HttpServlet;  
import javax.servlet.http.HttpServletRequest;  
import javax.servlet.http.HttpServletResponse;  
import javax.servlet.http.HttpSession;  
public class ProfileServlet extends HttpServlet {  
    protected void doGet(HttpServletRequest request, HttpServletResponse response)  
                      throws ServletException, IOException {  
        response.setContentType("text/html");  
        PrintWriter out=response.getWriter();  
        request.getRequestDispatcher("link.html").include(request, response);  
          
        HttpSession session=request.getSession(false);  
        if(session!=null){  
        String name=(String)session.getAttribute("name");  
          
        out.print("Hello, "+name+" Welcome to Profile");  
        }  
        else{  
            out.print("Please login first");  
            request.getRequestDispatcher("login.html").include(request, response);  
        }  
        out.close();  
    }  
}

File: web.xml

  
  
    
    
      
    LoginServlet  
    LoginServlet  
    LoginServlet  
    
    
    LoginServlet  
    /LoginServlet  
    
    
      
    ProfileServlet  
    ProfileServlet  
    ProfileServlet  
    
    
    ProfileServlet  
    /ProfileServlet  
    
    
      
    LogoutServlet  
    LogoutServlet  
    LogoutServlet  
    
    
    LogoutServlet  
    /LogoutServlet  
    

Output

If again you click on the profile link, you need to login first.