清晰了解session（清晰了解session）.docVIP

清晰了解session（清晰了解session） Questions about session (2009-10-09 17:11:30) reprinted labels: it 1 when will Session be created? Session is created in the client access, but the fact is that until a server program called HttpServletRequest.getSession (true) this statement was created, note that if JSP did not show the use of %@page Session= false Session JSP file% closed, the compiled Servlet will automatically add a HttpSession statement Session = HttpServletRequest.getSession (true); this is also implied in the JSP Session object. Since Session consumes memory resources, it should be closed in all JSP if it is not intended to use Session. 2. When will Session be deleted? Session is deleted in the following circumstances: The A. program calls HttpSession.invalidate (); B. distance from a timeout interval Session ID client sends more than Session (session timeout refers to a certain time not to the server sends a request, and not from the user login to the start time.) Set up; The C. server process is stopped (non persistent Session). 3, how do you want to delete Session when the browser closes? Strictly speaking, you cant do this (except sending a request for failure to the server at the same time). We often see that it seems that the browser was closed, as if session was cleared. But in fact, the session value has not been cleared, but is not the browser cache session ID value, if your browser cache folder in the open state at this time, even if you close the browser, the session value of ID still exists (until session server timeout failure, it will fail). If you want to turn off the browser cache folder (IE:ie- delete temporary files, when you close the browser in most other browsers is off by default). The only thing you can do is to use the JavaScript code window.oncolose to monitor the browsers closing action on all client pages, and then send a request to the server to delete the Session. But for the browser crash or forced to kill the process of these unconven