在传统发布订阅模型中,消息能够确保通知给每个感兴趣的订阅者,但前提是消息发布时订阅者在线且其订阅为全网共知.但若订阅者对其加入网络之前所发布的消息感兴趣,或处于时断时续的漫游状态,则其无从获得通知.在发布订阅系统中引入缓存机制,就是为了解决这一问题.本文提出一种基于哈希的路径缓存协议,将消息存储在投递路径上的代理及其邻居处.通过哈希函数选择消息缓存位置,并扩展了缓存路由信息以支持缓存内容的查找.另外,为将缓存冗余度控制在适当水平,本文利用网络特征和用户的历史请求信息,根据两个目标函数来解决缓存冗余和副本放置问题. In a traditional publish-subscribe model, a message ensures that every interested subscriber is notified, provided that the subscriber is online at the moment of the message and their subscription is known to the entire network, but if subscribers publish before they join the network The message is interested in, or in the intermittent roaming state, then it can not get the notice.In the subscription system, the introduction of the caching mechanism is to solve this problem.This paper proposes a hash-based path cache protocol, the message The agent and its neighbors stored in the delivery path select the message cache location by hash function and extend the cache routing information to support the lookup of the cache content.In addition, in order to control the redundancy of the cache at an appropriate level, Characteristics and user’s historical request information, according to two objective functions to solve the problem of cache redundancy and copy placement.