這裡主要介紹一下基於xml的配置：

1. 在pom.xml檔案中引入所需依賴

<!-- spring-session begin-->
    <dependency>
        <groupId>org.springframework.data</groupId>
        <artifactId>spring-data-redis</artifactId>
        <version>1.7.6.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>org.springframework.session</groupId>
        <artifactId>spring-session</artifactId>
        <version>1.3.0.RELEASE</version>
    </dependency>
    <dependency>
        <groupId>redis.clients</groupId>
        <artifactId>jedis</artifactId>
        <version>2.8.1</version>
    </dependency>
 

2.Redis配置檔案中配置以下資訊（注：官網中說配置LettuceConnectionFactory資訊，或者其他文件中說配置JedisConnectionFactory資訊，都是一個意思，其實LettuceConnectionFactory和JedisConnectionFactory都實現了RedisConnectionFactory介面，具體檢視https://www.2cto.com/kf/201705/638410.html）：

        <bean id="connectionFactory"
		    class="org.springframework.data.redis.connection.jedis.JedisConnectionFactory"
		p:host-name="${redis.host}" p:port="${redis.port}" p:password="${redis.pass}"
		p:pool-config-ref="poolConfig" p:database="14"/>
	<bean id="redisHttpSessionConfiguration"
		  class="org.springframework.session.data.redis.config.annotation.web.http.RedisHttpSessionConfiguration">
		<property name="maxInactiveIntervalInSeconds" value="9999999" />
	</bean>
 

通過官網上“We use the combination of <context:annotation-config/> and RedisHttpSessionConfiguration because Spring Session does not yet provide XML Namespace support (see gh-104). This creates a Spring Bean with the name of springSessionRepositoryFilter that implements Filter. The filter is what is in charge of replacing the 

3.其他地方大多數都是在web.xml中配置過濾器，如下配置：

<!-- spring-session -->
<filter>
    <filter-name>springSessionRepositoryFilter</filter-name>
    <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>
<filter-mapping>
    <filter-name>springSessionRepositoryFilter</filter-name>
    <url-pattern>/*</url-pattern>
    <dispatcher>REQUEST</dispatcher>
    <dispatcher>ERROR</dispatcher>
</filter-mapping>

在這是通過java配置過濾器，只要繼承org.springframework.session.web.context.AbstractHttpSessionApplicationInitializer抽象類即可，在這個類中會自動裝配。重寫beforeSessionRepositoryFilter方法和afterSessionRepositoryFilter方法。

beforeSessionRepositoryFilter方法，載入的是必要資訊；afterSessionRepositoryFilter方法新增一些自己配置的過濾器。

    @Override
    protected void beforeSessionRepositoryFilter(ServletContext servletContext) {
        // Create the dispatcher servlet's Spring application context
        AnnotationConfigWebApplicationContext dispatcherServlet = new AnnotationConfigWebApplicationContext();
        dispatcherServlet.register(MvcConfig.class);
        dispatcherServlet.setServletContext(servletContext);
        servletContext.addListener(new ContextLoaderListener(dispatcherServlet));
        dispatcherServlet.scan("com.qxs.web.config.MvcConfig");

	ServletRegistration.Dynamic registration = servletContext.addServlet("dispatcher", new DispatcherServlet(dispatcherServlet));
        registration.setLoadOnStartup(1);
        registration.addMapping("/");
    }

    @Override
    protected void afterSessionRepositoryFilter(ServletContext servletContext) {
        DelegatingFilterProxy delegatingFilterProxy = new DelegatingFilterProxy();
        servletContext.addFilter("shiroFilter", delegatingFilterProxy)
		 .addMappingForUrlPatterns(EnumSet.of(DispatcherType.REQUEST), false, "/*");

        //add UTF-8 filter
        final CharacterEncodingFilter characterEncodingFilter = new CharacterEncodingFilter();
        characterEncodingFilter.setEncoding("UTF-8");
        characterEncodingFilter.setForceEncoding(false);
        servletContext.addFilter("characterEncodingFilter", characterEncodingFilter)
        			 .addMappingForUrlPatterns(EnumSet.of(DispatcherType.REQUEST), false, "/*");

        //Todo - add SiteMeshFilter

        SiteMeshFilter siteMeshFilter = new SiteMeshFilter();
        servletContext.addFilter("siteMeshFilter", siteMeshFilter)
		 .addMappingForUrlPatterns(EnumSet.of(DispatcherType.REQUEST), false, "/*");

        OpenEntityManagerInViewFilter openEntityManagerInViewFilter = new OpenEntityManagerInViewFilter();
        openEntityManagerInViewFilter.setEntityManagerFactoryBeanName("entityManagerFactory");
        servletContext.addFilter("openEntityManagerInViewFilter", openEntityManagerInViewFilter)
		 .addMappingForUrlPatterns(EnumSet.of(DispatcherType.REQUEST), false, "/*");
    }

4.在啟動的過程中會執行AbstractHttpSessionApplicationInitializer的onStartup(ServletContext sevletContext)方法，呼叫insertSessionRepositoryFilter方法,然後裝配springSessionRepositoryFilter過濾器。

至此，Spring Session + Redis 實現共享session就結束了。