Servlet HttpSession Arayüzü

Giriş
Şu satırı dahil ederiz.

import javax.servlet.http.HttpSession;

constructor

Şöyle yaparız.

HttpSession session = request.getSession(true);  

Açıklaması şöyle.

When we use HttpServletRequest getSession() method and it creates a new request, it creates the new HttpSession object and also add a Cookie to the response object with name JSESSIONID and value as session id. This cookie is used to identify the HttpSession object in further requests from client.

Yani JSESSIONID çerezi servlet uygulamaları tarafından otomatik yaratılır.

Bu JSESSIONID'nin nasıl kullanıldığına dair açıklama şöyle. Açıklama PHP için ancak mantık aynı.

As the name suggests, users have control over client-side technologies like browsers that store and send cookies. Therefore, instead of leaving sensitive data on browsers, where it can be read and modified, most developers – and PHP – leave a unique, identifiable key on the browser, and establish communication with the server using that key.
...
In a similar way, whenever a user makes a request, a session ID is sent along with it. PHP finds the session related to this cookie and initializes a session object containing sensitive data, such as your email address or account balance, which allows the website to manage the user's session.

getAttribute metodu

Şöyle yaparız.

session.getAttribute("myObject");

invalidate metodu
Şöyle yaparız.

HttpSession session = ...;
session.invalidate();

removeAttribute metodu
Şöyle yaparız.

session.removeAttribute("myObject");

setAttribute metodu
Şöyle yaparız.

session.setAttribute("myObject", myBean);