Programming Tutorials

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The Session Object in JSP

By: Sathya Narayana in JSP Tutorials on 2010年10月24日 [フレーム]

The Session object in JSP provides a way to maintain state information across multiple requests made by the same client. It is an instance of the HttpSession class and can be obtained using the request.getSession() method.

The Session object provides a number of methods to manage session information. Some of the commonly used methods are:

setAttribute(String name, Object value): Sets the value of an attribute with the specified name in the session.
getAttribute(String name): Returns the value of the attribute with the specified name in the session.
removeAttribute(String name): Removes the attribute with the specified name from the session.
invalidate(): Invalidates the session, removing all attributes and ending the session.

Here's an example of how to use the Session object in a JSP:

<%@ page import="javax.servlet.http.HttpSession" %>
<%
 // Get the session object
 HttpSession session = request.getSession();
 
 // Set an attribute in the session
 session.setAttribute("username", "john");
 
 // Get an attribute from the session
 String username = (String) session.getAttribute("username");
 
 // Remove an attribute from the session
 session.removeAttribute("username");
 
 // Invalidate the session
 session.invalidate();
%>

In this example, we first obtain the Session object using the request.getSession() method. We then set an attribute named "username" in the session using the setAttribute() method, and retrieve its value using the getAttribute() method. We also remove the attribute using the removeAttribute() method and invalidate the session using the invalidate() method.