SpringSession2+SpringDataRedis2+spring5

• 相关配置
  整合一下新版本的配置，spring-session主要配置是下面这两个，另外redis、hiberhate、spring的配置底部有源码
  applicationContext-session.xml

  
  <beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
      http://www.springframework.org/schema/beans/spring-beans.xsd">
  
  
  
  
  
  <bean class="org.springframework.session.data.redis.config.annotation.web.http.RedisHttpSessionConfiguration">
      <property name="maxInactiveIntervalInSeconds" value="60" />
  bean>
  beans>

  web.xml

  
    <filter>
      <filter-name>springSessionRepositoryFilterfilter-name>
      <filter-class>org.springframework.web.filter.DelegatingFilterProxyfilter-class>
    filter>
    <filter-mapping>
      <filter-name>springSessionRepositoryFilterfilter-name>
      <url-pattern>/*url-pattern>
    filter-mapping>

• 依赖关系
  spring-session-data-redis和spring-session-core这两个包在阿里云没有，版本不对会
  

• 创建和清除session
  1、请求进入，调用httpSessionRepositoryFilter过滤器的doFilterInternal方法

  @Override
      protected void doFilterInternal(HttpServletRequest request,
              HttpServletResponse response, FilterChain filterChain)
              throws ServletException, IOException {
          request.setAttribute(SESSION_REPOSITORY_ATTR, this.sessionRepository);
  
          SessionRepositoryRequestWrapper wrappedRequest = new SessionRepositoryRequestWrapper(
                  request, response, this.servletContext);
          SessionRepositoryResponseWrapper wrappedResponse = new SessionRepositoryResponseWrapper(
                  wrappedRequest, response);
  
          try {
              filterChain.doFilter(wrappedRequest, wrappedResponse);
          }
          finally {
              //这个还没有执行
              wrappedRequest.commitSession();
          }
      }

  2、在redis中创建session：调用httprequest（即SessionRepositoryRequestWrapper）的getSession方法，进而调用RedisOperationsSessionRepository的createSession方法创建session，最后执行上面的wrappedRequest.commitSession()。创建效果如下，TTL显示为360秒，也就是生存时间为我们配置的1分钟再加了5分钟
  
  3、清理redis中的session：RedisHttpSessionConfiguration（继承自SpringHttpSessionConfiguration）如下，该类配置了每分钟都会调用一下清理session的方法。cleanExpiredSessions每次调用都通过读数据（这里时间也加了5分钟）的方式通知redis，redis内部在读时会判断一下数据TTL是否过期再清除

  static final String DEFAULT_CLEANUP_CRON = "0 * * * * *";
  private String cleanupCron = DEFAULT_CLEANUP_CRON;
  
  @Override
      public void configureTasks(ScheduledTaskRegistrar taskRegistrar) {
          taskRegistrar.addCronTask(() -> sessionRepository().cleanupExpiredSessions(),
                  this.cleanupCron);
      }

  public void cleanExpiredSessions() {
          long now = System.currentTimeMillis();
          long prevMin = roundDownMinute(now);
  
          if (logger.isDebugEnabled()) {
              logger.debug("Cleaning up sessions expiring at " + new Date(prevMin));
          }
  
          String expirationKey = getExpirationKey(prevMin);
          Set