In this tutorial you will learn about the Servlet HttpSession Login Logout and its application with practical example.
Servlet HttpSession Login Logout
In previous article we have gone through with methods of HttpSession interface. Also we have tried an example for that, here we are going to do login and logout with session. Let’s get understand more about HttpSession Interface.
We need to create some html, servlet classes for this, get understand about them one by one.
index.html
This will be our Welcome page, here we keep three links first one will be for Login, second Logout and last one will be Profile, like below code.
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<html> <head> <title>W3adda</title> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> </head> <body> <h1>Example of Session Login Logout</h1> <a href="login_session.html">Login</a>| <a href="LogoutSession">Logout</a>| <a href="ProfileSession">Profile</a> </body> </html> |
link_session.html
This is our link page, suppose we clicked directly on profile without login so this page will show us or even we did logout. Check below code.
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<html> <head> <title>W3adda</title> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> </head> <body> <a href="login_session.html">Login</a> | <a href="LogoutSession">Logout</a> | <a href="ProfileSession">Profile</a> </body> </html> |
login_session.html
This will call from index.html file or link_session.html file, when user will click on Login button.
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<html> <head> <title>W3adda</title> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> </head> <body> <form action="LoginSession" method="post"> Name:<input type="text" name="name"><br> Password:<input type="password" name="password"><br> <input type="submit" value="login"> </form> </body> </html> |
LoginSession.java
This is our Login file, here I have taken “w3adda1234” as a password, if password matched so it stores the attribute into the session. Check below code.
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package SessionLoginLogout; 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 LoginSession extends HttpServlet { /** * Processes requests for both HTTP <code>GET</code> and <code>POST</code> * methods. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=UTF-8"); } // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code."> /** * Handles the HTTP <code>GET</code> method. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } /** * Handles the HTTP <code>POST</code> method. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); response.setContentType("text/html"); PrintWriter out=response.getWriter(); request.getRequestDispatcher("link_session.html").include(request, response); String name=request.getParameter("name"); String password=request.getParameter("password"); if(password.equals("w3adda1234")){ out.print("Welcome to w3adda.com :"+name); HttpSession session=request.getSession(); session.setAttribute("name",name); } else{ out.print("Sorry, username or password error!"); request.getRequestDispatcher("login_session.html").include(request, response); } out.close(); } /** * Returns a short description of the servlet. * * @return a String containing servlet description */ @Override public String getServletInfo() { return "Short description"; }// </editor-fold> } |
ProfileSession.java
With the help of session.getAttribute(“name”) we will get the value of attribute which is stored in the session. Check below code.
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package SessionLoginLogout; 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 ProfileSession extends HttpServlet { /** * Processes requests for both HTTP <code>GET</code> and <code>POST</code> * methods. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=UTF-8"); } // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code."> /** * Handles the HTTP <code>GET</code> method. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); PrintWriter out=response.getWriter(); request.getRequestDispatcher("link_session.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_session.html").include(request, response); } out.close(); } /** * Handles the HTTP <code>POST</code> method. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } /** * Returns a short description of the servlet. * * @return a String containing servlet description */ @Override public String getServletInfo() { return "Short description"; }// </editor-fold> } |
LogoutSession.java
From here we will destroy session. Check below code.
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package SessionLoginLogout; 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 LogoutSession extends HttpServlet { /** * Processes requests for both HTTP <code>GET</code> and <code>POST</code> * methods. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setContentType("text/html;charset=UTF-8"); } // <editor-fold defaultstate="collapsed" desc="HttpServlet methods. Click on the + sign on the left to edit the code."> /** * Handles the HTTP <code>GET</code> method. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); PrintWriter out=response.getWriter(); request.getRequestDispatcher("link_session.html").include(request, response); HttpSession session=request.getSession(); session.invalidate(); out.print("You are successfully logged out!"); out.close(); } /** * Handles the HTTP <code>POST</code> method. * * @param request servlet request * @param response servlet response * @throws ServletException if a servlet-specific error occurs * @throws IOException if an I/O error occurs */ @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { processRequest(request, response); } /** * Returns a short description of the servlet. * * @return a String containing servlet description */ @Override public String getServletInfo() { return "Short description"; }// </editor-fold> } |
Output:-
As we are done with code, so let’s run this and get output like below images.
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Screen 5:-
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