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This article uses easy-to-understand examples to introduce Redis how to achieve Session sharing, the code is very detailed, interested friends can refer to, hope to be helpful to you.

Session sharing based on Redis

These days to do session sharing such a small module, also looked up a lot of information, gave me the feeling, is too chaotic, I can not find what I want, almost all the implementation methods are different from my idea, here, I summarize how I use Redis to achieve session sharing, to facilitate their own future query, but also hope to give friends with this need some help.

First of all, let's talk about my development environment: nginx, redis, tomcat, build the project with moven and run the jetty server, so here, I will also talk about how to use maven to pack war packages and deploy them to run on tomcat.

Redis is a key-value database, the stored value, it all depends on this key, here a long sentence, because the original, professional introduction I do not paste, want to know the official introduction can be self-search.

Configuration in pom.xml:

Redis.clients jedis 2.8.1 org.springframework.data spring-data-redis 1.7.2.RELEASE

Configuration in aplicationContext-redis.xml

After the configuration is complete, start the code implementation:

In LoginController:

First step, introduce RedisTemplate

@ Autowired @ Qualifier ("writeRedisTemplate") private StringRedisTemplate writeTemplate

Here, you only need to introduce writeRedisTemplate. When you log in, you are only responsible for writing, and you need to read it only when you refresh it again and go through the filter.

The second step is the normal login process. After a successful login, request also needs to save session information.

The third step is to set the cookie value and store the key value in redis as saving userSession information into cookie. When refreshing the browser, the filter can get the key value from cookie, and then go to redis to get the corresponding value, that is, userSession.

String domain = request.getServerName (); String cookieId=MD5Util.MD5Encode ("uasLoginer", "UTF-8"); / / generate token, which is used as the key value of session in redis storage StringredisSessionKey= UUID.randomUUID (). ToString (); Cookie uasLoginer = new Cookie (cookieId, redisSessionKey); if (domain.startsWith ("uas.")) {uasLoginer.setDomain (domain.substring (4 uas.)) } else {uasLoginer.setDomain (domain);} uasLoginer.setMaxAge (60000); uasLoginer.setPath ("/"); response.addCookie (uasLoginer)

Here cookie cross-domain setDomain and setPath settings

The fourth step is to store userSession information in redis

If the value of writing redis in RedisTemplate is of type String, you need to convert the userSession object into a Json string.

UserSessionString = JSON.toJSONString (userSession)

During the conversion to Json, the import of import com.alibaba.fastjson.JSON; failed all the time. It was found that there is no dependency on Json in pom. If you encounter the same problem, you can check whether there is a dependency on json in pom.xml. If not, import the dependency of json in pom.xml as follows:

Net.sf.json-lib json-lib 2.3 jdk15

The code written to redis is as follows:

WriteTemplate.opsForHash () .put (UasContants.REDIS_USER_SESSION_KEY+ "_" + redisSessionKey,redisSessionKey, userSessionString); writeTemplate.expire (UasContants.REDIS_USER_SESSION_KEY+ "_" + redisSessionKey, 1800L, TimeUnit.SECONDS); / / set the validity period of the median value of redis

After this operation, the user's session information has been stored in redis, which can be checked in redis.

Step 5: after entering the page, refresh the page, the request will go through the filter, read the value of redis in Filter.Java and do some processing

In the case of the filter, redisTemplate cannot be introduced through annotations, but can be introduced in the following ways:

BeanFactory beans = WebApplicationContextUtils.getWebApplicationContext (request.getSession (). GetServletContext ()); StringRedisTemplate readTemplate = (StringRedisTemplate) beans.getBean ("readRedisTemplate"); StringRedisTemplate writeTemplate = (StringRedisTemplate) beans.getBean ("writeRedisTemplate")

The filter takes the key value of redis from cookie and reads out the value value with readTemplate

String cookid=MD5Util.MD5Encode ("uasLoginer", "UTF-8"); Cookie [] cookies = req.getCookies (); String redisSessionKey = ""; if (cookies! = null) {for (Cookie cookie: cookies) {if (cookie.getName (). Equals (cookid)) {redisSessionKey = cookie.getValue ();}} UserSession userSession = null String userSessionString = (String) readTemplate.boundHashOps (UasContants.REDIS_USER_SESSION_KEY+ "_" + redisSessionKey) .get (redisSessionKey); if (null! = userSessionString) {@ SuppressWarnings ("static-access") JSONObject obj = new JSONObject () .fromObject (userSessionString); / / convert json string to json object userSession = (UserSession) JSONObject.toBean (obj,UserSession.class); writeTemplate.expire (UasContants.REDIS_USER_SESSION_KEY+ "_" + redisSessionKey, 1800L, TimeUnit.SECONDS) Request.getSession () .setAttribute (UasContants.USER_SESSION, userSession);} if (userSession! = null) {chain.doFilter (req, res); return;} else {res.sendRedirect (UasContants.LOGIN_URL); return;}

Here, additional information about the configuration of web.xml and LoginFilter is attached. If necessary, please refer to:

Org.springframework.web.context.ContextLoaderListener loginFilter com.sfbest.uas.filter.LoginFilter excludePaths / login,/user/login,/user/auth loginFilter / *

According to the above configuration, we can use redis to achieve session sharing, but when I was developing, I encountered a painful problem in the test environment.

When the project is deployed on two tomcat servers, the key value of redis can not be stored in cookie, and a single one can be stored after long-term testing.

Finally found that the problem is the configuration of nginx, as a warning, a deep shadow. I will post the configuration code of my normal running nginx below.

Upstream uassessiontest.d.com {server 10.103.16.226 purl 8088; server 10.103.16.226 purl 8089 } server {log_format sf_uastest'$remote_addr-$remote_user [$time_local] "$request"'$status $body_bytes_sent "$http_referer"'"$http_user_agent" $http_cookie'; listen 80 Server_name uassessiontest.d.com; access_log / var/log/nginx/uassessiontest.log sf_uastest; location / {rewrite ^ / $/ uas/ break; proxy_pass http://uassessiontest.d.com;}}

The red ones are the original rare parts, which are used to write cookie values to the browser.

On how to achieve Session sharing on Redis to share here, I hope the above content can be of some help to you, can learn more knowledge. If you think the article is good, you can share it for more people to see.

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