web session tracking cookies and sessions

1. Introduction to Cookies

     cookie: Data stored on the client to maintain session state.

    

 

//create a cookie
Cookie cookie = new Cookie(name , value);
//pass the cookie to the client
response.addCookie(cookie );

 

 

    The client will return a cookie every time it visits, and the server will traverse the cookie code

 

Cookie[] cookies = request.getCookies();
	 if(null != cookies && cookies.length > 0){
		 for(Cookie cookie : cookies){
                      // Find the target cookie by traversing
		 }
		 
	 }

 

 

     Removal of cookies

      

//1. When the parameter is negative, the browser writes the cookie into the browser memory (the default is memory storage)
//2. When set to 0, the browser will remove the cookie
//3. When it is a positive number, it will be persisted to the hard disk and deleted after the specified time
cookie.setMaxAge(0);
//Write the cookie back to the browser and notify the browser to delete the cookie
response.addCookie(cookie);