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Editor to share with you how to use interceptors to achieve login authentication function in the SSM project, I believe most people do not know much about it, so share this article for your reference. I hope you will gain a lot after reading this article. Let's learn about it together.

Implementation of login interface

Public User queryUser (String UserName, String Password,HttpServletRequest request, HttpServletResponse response) {User user = userMapper.queryUser (UserName,Password); if (! StringUtils.isEmpty (user)) {/ / 1. Get session HttpSession session = request.getSession (); / / 2. Get sessionid String sessionId = session.getId (); / / 3. Put sessionid as key and user information user as value into session.setAttribute (sessionId,user) in session; / / 4. Save sessionId to cookie, and "JSESSIONID" is the custom key value Cookie cookie = new Cookie ("JSESSIONID", sessionId); / / 5. Set the valid path cookie.setPath (request.getContextPath ()) of cookie; / / 6. Return cookie to page response.addCookie (cookie);} return user;}

Code ideas:

1. The user enters the account password and successfully logs in to get the user information (User)

two。 Get session and get sessionid (Note: every session object has a sessionid)

3. Put sessionid as key and user information (User) as value into session

4. Create a Cookie object and put "JSESSIONID" as key,sessionId as value in cookie

5. Set the valid path of cookie, return cookie to the page, and the page will receive the cookie message with key as "JSESSIONID" and value as sessionId, as shown in the following figure.

Interceptor class code implementation

Public class Filter extends HandlerInterceptorAdapter {private static Logger logger = Logger.getLogger (Filter.class); / * * the first method to enter the interceptor * if false is returned, the execution will not continue * if true is returned, the execution of * / @ Override public boolean preHandle (HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {/ / 1 will continue. Define the sessionid variable String sessionid = ""; / / 2. Get the session object HttpSession session=request.getSession (); / / 3. Get all the cookie Cookie [] cookies = request.getCookies () on the page; / / 4. Loop to find the cookie for (Cookie cookie:cookies) {if (cookie.getName (). Equals ("JSESSIONID")) {sessionid = cookie.getValue ();}} / / 5 named "JSESSIONID". Obtain user information according to sessionid User user = (User) session.getAttribute (sessionid); if (StringUtils.isEmpty (user)) {logger.info ("user not logged in"); / / user not logged in jumps to login page response.sendRedirect ("login"); return false;} logger.info ("user logged in") Return true;}}

Code ideas:

1. To customize an interceptor class, first inherit HandlerInterceptorAdapter and override the preHandle method, in which you write the logic code of the interceptor

two。 Get the cookies array, which has all the cookies information in the browser. Loop through to find the cookies whose name is "JSESSIONID" and get its value, which is sessionid.

3. Find the user object through sessionid. If you can get the object proof that you have logged in, if you cannot get the object certificate that you have not logged in,

4. Access the interface directly if you have logged in, and jump to the login page to log in if you have not logged in

Profile implementation

Configuration meaning:

1. When we use interceptors, we must specify which interfaces to intercept. First of all, we will intercept all interfaces.

two。 Then we found a problem. At this time, the login interface is also in the scope of blocking, so before we call the login interface normally, he will also intercept and judge whether the user has logged in. At this time, the user must not have logged in, so he will jump to the login interface again. If we log in again or jump to the login page, we can't log in all the time, so we need to configure the login interface to not block.

3. Then we specify the interceptor classpath that we have configured, and at this time we can perform login verification in this class.

4. This profile is a spring-mvc.xml profile

These are all the contents of the article "how to use interceptors to implement login authentication in the SSM project". Thank you for reading! I believe we all have a certain understanding, hope to share the content to help you, if you want to learn more knowledge, welcome to follow the industry information channel!

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