Login Session using JSP

In this tutorial, we will learn how to set the User session, validating the user details at the time of Login using JSP?
By: Vanka Manikanth, on 27 JAN 2017

For every user there will be a particular session, here we are validating the details of a user and setting the user in a session and finally we are invalidating the user.

Index.jsp

Here we are taking the input from the user and triggering the action to validate.jsp on submitting of the form.

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
		<title>Session In JSP</title>
		<style>
			h1{
				background-color:PINK;
				width:50%;
			}
			h2{
				text-decoration: underline;
			}
			td{
				padding:15px;
				width:50%;
			}
			legend{
				background-color:green;
			}
			fieldset{
				width:30%;
				height:70%;
				text-align:center;
			}
		</style>
	</head>
	<body>
		<h1>Session in JSP</h1>
		<h2>USER LOGIN SESSION</h2>
		<fieldset>
			<legend><font color="white"><b>Login Here:</b> </font></legend>
			<form action="validate.jsp" method="post"> <!-- Here we are taking the values from user and triggering the validate.jsp file -->
			<table>
				<tr><td>USER NAME</td><td><input type="text" name="username"></td></tr>
				<tr><td>PASS WORD</td><td><input type="password" name="password"></td></tr>
				<tr><td></td><td><button type="submit">LOGIN</button></td></tr>
			</table>
			</form>
		</fieldset>
	</body>
</html>

Validate.jsp

Here we are validating the particular user by getting the input values, and sending them to its respective pages.

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
		<title>Validate</title>
	</head>
	<body><!-- values given at login page are taken here and checks if the valid details are not -->
		<%
		String username=request.getParameter("username");
		String password=request.getParameter("password");
		if(username.equals("includehelp") && password.equals("includehelp")){
			//if the user is valid, then this block executes and WE ARE KEEPING THE USER IN A SESSION
			session.setAttribute("user", username);//THIS IS HOW WE DECLARE THE USER IN A SESSION
			response.sendRedirect("logged.jsp"); //AND WE REDIRECTED TO LOGIN PAGE
			
		}else{
			
			//IF THE USER IS NOT AUTHORISED THEN AGAIN HE WILL BE REDIRECTED TO THE SAME LOGIN PAGE
			response.sendRedirect("index.jsp");
		}
		%>
	</body>
</html>

Logged.jsp

Soon as the validation done, if the user is authorized according to our condition will be redirected to login page else forwarded to the same login page.

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
	<head>
	<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
		<title>Success</title>
	</head>
	<body>
		<%
		//HERE WE GETTING THE ATTRIBUTE DECLARED IN VALIDATE.JSP AND CHECKING IF IT IS NULL, THE USER WILL BE REDIRECTED TO LOGIN PAGE
				String uid = (String)session.getAttribute("user");
				if (uid == null)
				{
		%><!-- NOT A VALID USER, IF THE USER TRIES TO EXECUTE LOGGED IN PAGE DIRECTLY, ACCESS IS RESTRICTED -->
					 <jsp:forward page="index.jsp"/>
		<%	
				}
				else
				{//IF THE VALUE IN SESSION IS NOT NULL THEN THE IS USER IS VALID
					out.println(" <h1>You have successfully created the Session of User : " +uid+"</h1>");
					%>
					<!-- WE HAVE GIVEN LOGOUT.JSP FILE INORDER TO LOGOUT THE SESSION -->
					<a href="logout.jsp">Logout</a>
				<%}
		%> 
	</body>
</html>

Logout.jsp

Here we are just invalidating the user so that the values in the session would be invalidated.

<html>
	<body>
		<% session.invalidate(); %> <!-- HERE WE ARE INVALIDATE THE SESSION, SO THAT NO VALUES WILL BE PRESENT IN SESSION -->
		<jsp:forward page="index.jsp"/>
	</body>
<html>

NOTE: If you want to check clearly, try to run logged.jsp soon as you logged out, you will be redirected to login page. Hope you understood.

Output

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