1、cas ticket统一存储

　　做cas集群首先需要将ticket拿出来，做统一存储，以便每个节点访问到的数据一致。官方提供基于memcached的方案，由于项目需要，需要做计入redis，根据官方例子改了一个基于redis版本的。

public class RedisTicketRegistry extends AbstractDistributedTicketRegistry{
        @NotNull    private final RedisTemplate
     
       reidsTemplate;    /**     * TGT cache entry timeout in seconds.     */    @Min(0)    private final int tgtTimeout;    /**     * ST cache entry timeout in seconds.     */    @Min(0)    private final int stTimeout;        public RedisTicketRegistry(RedisTemplate
      
        reidsTemplate,int tgtTimeout,int stTimeout){        this.reidsTemplate=reidsTemplate;        this.tgtTimeout=tgtTimeout;        this.stTimeout=stTimeout;    }    @Override    public void addTicket(Ticket ticket) {        logger.debug("Adding ticket {}", ticket);        try {            reidsTemplate.opsForValue().set(ticket.getId(),ticket, getTimeout(ticket), TimeUnit.SECONDS);        } catch (final Exception e) {            logger.error("Failed adding {}", ticket, e);        }    }    @Override    public Ticket getTicket(String ticketId) {         try {                final Ticket t = (Ticket) this.reidsTemplate.opsForValue().get(ticketId);                if (t != null) {                    return getProxiedTicketInstance(t);                }            } catch (final Exception e) {                logger.error("Failed fetching {} ", ticketId, e);            }            return null;    }    @Override    public boolean deleteTicket(String ticketId) {         logger.debug("Deleting ticket {}", ticketId);            try {                 this.reidsTemplate.delete(ticketId);                 return true;            } catch (final Exception e) {                logger.error("Failed deleting {}", ticketId, e);            }            return false;    }    @Override    public Collection
       
         getTickets() {         throw new UnsupportedOperationException("GetTickets not supported.");    }    @Override    protected void updateTicket(Ticket ticket) {     logger.debug("Updating ticket {}", ticket);        try {              this.reidsTemplate.delete(ticket.getId());              reidsTemplate.opsForValue().set(ticket.getId(),ticket, getTimeout(ticket), TimeUnit.SECONDS);        } catch (final Exception e) {            logger.error("Failed updating {}", ticket, e);        }    }    @Override    protected boolean needsCallback() {        // TODO Auto-generated method stub        return true;    }   private int getTimeout(final Ticket t) {        if (t instanceof TicketGrantingTicket) {            return this.tgtTimeout;        } else if (t instanceof ServiceTicket) {            return this.stTimeout;        }        throw new IllegalArgumentException("Invalid ticket type");    }}
       
      
     

　　对应的ticketRegistry.xml的配置如下：

　　这里既然使用了redis作为ticket存储，就需要将原来的方案给注释掉：

　　到这里，cas的改进就OK了，下面就需要将session也做集群同步。

2、tomcat session集群同步

　　这里采用开源的tomcat-redis-session-manager,git hub地址为：https://github.com/jcoleman/tomcat-redis-session-manager

　　这里只使用的是jdk1.7，tomcat7，tomcat6需要重新编译好像。

　　1）拷贝编译打包之后的tomcat-redis-session-manager-VERSION.jar，jedis-2.5.2.jar，commons-pool2-2.2.jar到tomcat/lib目录下

　　2）修改Tomcat context.xml (or the context block of the server.xml if applicable.)

至此cas集群配置就可以了。