The difference between session and cookies

1、cookie Data is stored on the client ,session Data on the server .

2、cookie Because the data is stored on the client , So it's not very safe , Others can analyze the local COOKIE And carry on COOKIE cheating
   Should be used in consideration of safety session.

3、session It's time-sensitive , Usually follow tomcat, It's usually 30 minute ; But not every 30 Refresh every minutes , Generally, there is an action , Automatically move the time back 30 minute

Cookie Generally, there is no expiration time , It's usually the client , We will clear the browser cookie The operation of

For example, our login page , During the first visit , Will be in cookie Save our corresponding sessionid, The relevant information of the corresponding account is stored in session in , When we add it later 、 Delete and other operation requests , You don't need to enter the account password every time . Will pass in cookie Medium sessionid Go to the server and find the corresponding session Is it overdue , If there is expiration , Will jump to the login page ; If session Not expired , You can directly

How do you use it? ：

@PostMapping("/postStudent")// Insert students 
	public String postStudent(@RequestBody String name ,HttpServletRequest req,HttpServletResponse res) {
		req.getSession().setAttribute("student", "xiaoming");
		System.out.println(req.getSession().getId());
		System.out.println(name);
		return null;

	}

  adopt req.getSession().setAttribute("student", "xiaoming"); Put the corresponding session For storage , At this time, the sessionid Store in cookie in ;