Java meets html--jsp article: JSP built-in objects (bottom)

What is a session?

• Session represents a client-to-server conversation
• The session in the Web refers to the amount of time that a user has spent browsing a website, from entering the site to the browser closing, that is, the time it takes for the user to browse the site.
• As you can see from the above definition, the session is actually a specific time concept
• The session of different users is stored inside the server

Session Object

• The session object is a JSP built-in object.
• The session object is created automatically when the first JSP page is loaded, and sessions management is completed.
• Open a browser from a client and connect to the server to start, to the client close the browser to leave the end of this server, known as a session.
• When a client accesses a server, it may switch between several pages of the server, and the server should know by some means that it is a client and needs a session object.
• The session object is an instance of the Htppsession class.

The following are common methods for session objects:

The life cycle of the session

Create: When a client accesses a JSP or servlet for the first time, the server creates a SessionID for the current session, and each time the client sends a request to the server, it carries the SessionID in the past. This seesionid will be verified by the server.

Activities:

• A new page that is opened by a hyperlink in a session belongs to the same session.
• As long as the current session page does not close all, reopen the new browser window to access the same project resource when it belongs to the same session.
• Unless all the pages of this session are closed and then re-access a JSP or the servlet will create a new session.

Note: Note that the original session still exists, but the old SessionID still exist on the server, but no more clients carry it and then to the server check.

Destroyed:

There are only three ways to destroy a session:

1, call the Session.invalidate () method

2. Session expires (Timeout)

3. Server restart

Application object:

Common methods for application objects are as follows:

Page Object

PageContext Object

Common methods for PageContext objects are as follows:

Config object

Exception Object

Java meets html--jsp article: JSP built-in objects (bottom)