spring-session+redis解决session共存问题

原文地址：http://docs.spring.io/spring-session/docs/current/reference/html5/guides/httpsession.html

Spring Session - HttpSession (Quick Start)

Rob WinchVersion 1.3.1.RELEASE

Table of Contents
Updating
Dependencies
Spring
Java Configuration
Java
Servlet Container Initialization
httpsession
Sample Application
Running
the httpsession Sample Application
Exploring
the httpsession Sample Application
How
does it work?

This guide describes how to use Spring Session to transparently leverage Redis to back a web application’s 

HttpSession

 with
Java Configuration.

The completed guide can be found in the httpsession sample application.

Updating
Dependencies

Before you use Spring Session, you must ensure to update your dependencies. If you are using Maven, ensure to add the following dependencies:

pom.xml

<dependencies>
<!-- ... -->

<dependency>
<groupId>org.springframework.session</groupId>
<artifactId>spring-session-data-redis</artifactId>
<version>1.3.1.RELEASE</version>
<type>pom</type>
</dependency>
<dependency>
<groupId>biz.paluch.redis</groupId>
<artifactId>lettuce</artifactId>
<version>3.5.0.Final</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>4.3.4.RELEASE</version>
</dependency>
</dependencies>

Spring
Java Configuration

After adding the required dependencies, we can create our Spring configuration. The Spring configuration is responsible for creating a Servlet Filter that replaces the 

HttpSession

 implementation
with an implementation backed by Spring Session. Add the following Spring Configuration:

@EnableRedisHttpSession
public class Config {

@Bean
public LettuceConnectionFactory connectionFactory() {
return new LettuceConnectionFactory();
}
}

	The  @EnableRedisHttpSession  annotation creates a Spring Bean with the name of  springSessionRepositoryFilter that implements Filter. The filter is what is in charge of replacing the  HttpSession  implementation to be backed by Spring Session. In this instance Spring Session is backed by Redis.
	We create a  RedisConnectionFactory  that connects Spring Session to the Redis Server. We configure the connection to connect to localhost on the default port (6379) For more information on configuring Spring Data Redis, refer to the reference documentation.

Java
Servlet Container Initialization

Our Spring Configuration created
a Spring Bean named 

springSessionRepositoryFilter

 that
implements 

Filter

. The 

springSessionRepositoryFilter

 bean
is responsible for replacing the 

HttpSession

 with
a custom implementation that is backed by Spring Session.

In order for our 

Filter

 to do its magic,
Spring needs to load our 

Config

 class. Last
we need to ensure that our Servlet Container (i.e. Tomcat) uses our 

springSessionRepositoryFilter

 for
every request. Fortunately, Spring Session provides a utility class named 

AbstractHttpSessionApplicationInitializer

 both
of these steps extremely easy. You can find an example below:

src/main/java/sample/Initializer.java

public class Initializer extends AbstractHttpSessionApplicationInitializer {

public Initializer() {
super(Config.class);
}
}

The name of our class (Initializer) does not matter. What is important is that we extend  AbstractHttpSessionApplicationInitializer .

	The first step is to extend  AbstractHttpSessionApplicationInitializer . This ensures that the Spring Bean by the name  springSessionRepositoryFilter  is registered with our Servlet Container for every request.
	AbstractHttpSessionApplicationInitializer  also provides a mechanism to easily ensure Spring loads our  Config .

httpsession
Sample Application

Running
the httpsession Sample Application

You can run the sample by obtaining the source code and invoking the following
command:

For the sample to work, you must install Redis 2.8+ on localhost and run it with the default port (6379). Alternatively, you can update the  LettuceConnectionFactory  to point to a Redis server.

$ ./gradlew :samples:httpsession:tomcatRun

You should now be able to access the application at http://localhost:8080/

Exploring
the httpsession Sample Application

Try using the application. Fill out the form with the following information:

Attribute Name: username

Attribute Value: rob

Now click the Set Attribute button. You should now see the values displayed in the table.

How
does it work?

We interact with the standard 

HttpSession

 in
the 

SessionServlet

 shown below:

src/main/java/sample/SessionServlet.java

@WebServlet("/session")
public class SessionServlet extends HttpServlet {

@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
String attributeName = req.getParameter("attributeName");
String attributeValue = req.getParameter("attributeValue");
req.getSession().setAttribute(attributeName, attributeValue);
resp.sendRedirect(req.getContextPath() + "/");
}

private static final long serialVersionUID = 2878267318695777395L;
}

Instead of using Tomcat’s 

HttpSession

, we
are actually persisting the values in Redis. Spring Session creates a cookie named SESSION in your browser that contains the id of your session. Go ahead and view the cookies (click for help with Chrome or Firefox).

If you like, you can easily remove the session using redis-cli. For example, on a Linux based system you can type:

$ redis-cli keys '*' | xargs redis-cli del

The Redis documentation has instructions for installing redis-cli.

Alternatively, you can also delete the explicit key. Enter the following into your terminal ensuring to replace 

7e8383a4-082c-4ffe-a4bc-c40fd3363c5e

 with
the value of your SESSION cookie:

$ redis-cli del spring:session:sessions:7e8383a4-082c-4ffe-a4bc-c40fd3363c5e

Now visit the application at http://localhost:8080/ and observe that the attribute we added is no longer displayed.

Version 1.3.1.RELEASE

Last updated 2017-04-27 18:42:57 +00:00