How does spring MVC get the session value to the foreground, mvcsession

How does spring MVC get the session value to the foreground, mvcsession

Session Introduction

In WEB development, the server can create a session object (session Object) for each user's browser. Note: a browser exclusively occupies a session object (by default ). Therefore, when you need to save user data, the server program can write user data to the session exclusively occupied by the user's browser. When you use the browser to access other programs, other programs can extract the user data from the user's session to serve the user.

 

 

Obtain the session in the background:

@ RequestMapping ("/usrlogin ")
Public ModelAndView usrlogin (@ RequestParam String usrid,
@ RequestParam String passwd ){
HttpSession session = getSession ();
User user = new User ();
User = userMapper. getUserByUsridAndPasswd (usrid, passwd );
If (null! = User ){
Session. setAttribute ("user", user. getUser_id ());
// User user1 = (User) session. getAttribute ("user ");
// System. out. println (user1.getUser _ name ());

Return new ModelAndView ("main ");
} Else {
Return new ModelAndView ("error ");
}
}


Public static HttpSession getSession (){
HttpSession session = null;
Try {
Session = getRequest (). getSession ();
} Catch (Exception e ){}
Return session;
}

Public static HttpServletRequest getRequest (){
ServletRequestAttributes attrs = (ServletRequestAttributes) RequestContextHolder. getRequestAttributes ();
Return attrs. getRequest ();
}

 

Foreground jsp values:

 <%        HttpSession s = request.getSession();       %><span><%=s.getAttribute("user")%></span>