Spring boot + redis realizes session sharing

This time I bring a tutorial on spring boot + redis to achieve session sharing.

In the spring boot documentation, we are told to add @EnableRedisHttpSession to enable spring session support. The configuration is as follows:

Java code

@Configuration  
@EnableRedisHttpSession  
public class RedisSessionConfig {  
}

The annotation @EnableRedisHttpSession is provided by spring-session-data-redis, so add it in the pom.xml file:

<dependency>  
        <groupId>org.springframework.boot</groupId>  
        <artifactId>spring-boot-starter-redis</artifactId>  
</dependency>  
<dependency>  
        <groupId>org.springframework.session</groupId>  
        <artifactId>spring-session-data-redis</artifactId>  
</dependency>

Next, you need to configure the location of the redis server in application.properties. Here, we use this machine:

spring.redis.host=localhost  
spring.redis.port=6379

In this way, the simplest spring boot + redis to achieve session sharing is completed, and the next test is performed.

First, we open two tomcat services, the ports are 8080 and 9090, and set them in application.properties :

server.port=8080

Next define a Controller:

@RestController  
@RequestMapping(value = "/admin/v1")  
public class QuickRun {  
    @RequestMapping(value = "/first", method = RequestMethod.GET)  
    public Map<String, Object> firstResp (HttpServletRequest request){  
        Map<String, Object> map = new HashMap<>();  
        request.getSession().setAttribute("request Url", request.getRequestURL());  
        map.put("request Url", request.getRequestURL());  
        return map;  
    }  
  
    @RequestMapping(value = "/sessions", method = RequestMethod.GET)  
    public Object sessions (HttpServletRequest request){  
        Map<String, Object> map = new HashMap<>();  
        map.put("sessionId", request.getSession().getId());  
        map.put("message", request.getSession().getAttribute("map"));  
        return map;  
    }  
}

启动之后进行访问测试，首先访问8080端口的tomcat，返回：

{"request Url":"http://localhost:8080/admin/v1/first"}

接着，我们访问8080端口的sessions，返回：

{ "sessionId":"efcc85c0-9ad2-49a6-a38f-9004403776b5","message":"http://localhost:8080/admin/v1/first"}

最后，再访问9090端口的sessions，返回：

{"sessionId":"efcc85c0-9ad2-49a6-a38f-9004403776b5","message":"http://localhost:8080/admin/v1/first"}

可见，8080与9090两个服务器返回结果一样，实现了session的共享

如果此时再访问9090端口的first的话，首先返回：

{"request Url":"http://localhost:9090/admin/v1/first"}

而两个服务器的sessions都是返回：

{ "sessionId":"efcc85c0-9ad2-49a6-a38f-9004403776b5","message":"http://localhost:9090/admin/v1/first"}

通过spring boot + redis来实现session的共享非常简单，而且用处也极大，配合nginx进行负载均衡，便能实现分布式的应用了。

本次的redis并没有进行主从、读写分离等等配置(_(:з」∠)_其实是博主懒，还没尝试过.......)

而且，nginx的单点故障也是我们应用的障碍......以后可能会有对此次博客的改进版本，比如使用zookeeper进行负载均衡，敬请期待。

Spring boot + redis realizes session sharing

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