cookie和session的作用及其区别（The function and difference between cookie and session）.docVIP

cookie和session的作用及其区别（The function and difference between cookie and session） First, the difference between the cookie mechanism and the session mechanism Specifically, the cookie mechanism employs a scheme that maintains the state at the client side, while the session mechanism uses a scheme that maintains the state at the server side. At the same time, we also see that because the server maintains the state of the program in the client is also required to save a logo, so the session mechanism may need the help of cookie mechanism to achieve the purpose of preservation of identity, but in fact there are other options. Two, the difference between session cookie and persistent cookie If you do not set expiration time, the cookie life cycle is declared during the browser session. As long as the browser window is closed, cookie disappears. This lifetime is the cookie for browsing sessions, known as session cookie. Session cookie is generally not stored on the hard disk but stored in memory. If the expiration date is set, the browser saves the cookie to the hard disk and opens the browser again after closing. These cookie are still valid until the expiration date is set. The cookie stored on the hard disk can be shared among different browser processes, such as two IE windows. As for cookie stored in memory, different browsers have different ways of dealing with it Three, how to use to achieve automatic login When a user registers on a web site, he receives a unique user ID cookie. The customer then re connection, the user ID will automatically return to the server, to check on it, determine whether it is a registered user and select the automatic login, so users need not give a clear user name and password, you can access the server resources. Four, how to customize the site according to the users preferences? The site can use cookie to record user wishes. For simple settings, the web site can store the settings of the page directly in cookie for customization. However