在P2P技术的应用过程中，需要考虑的问题甚多，包括网络中共享文件的发现机制，数据传输的完整性和传输过程中的效率和安全性问题，还包括网络中节点的负载均衡问题等等。本文主要完成了下面几个工作：1)采用基于超节点的混合型P2P网络拓扑结构，列出常见的资源定位搜索算法，进行比较，并选择Chord算法作为本系统资源定位搜索算法的基础，做出改进。

2)设计系统框架。将P2P应用系统的结构分为拥有设置和显示功能的用户应用层，拥有文件共享机制和节点发现及超节点选择机制的通知层和拥有文件上传和下载功能的网络传输层。从功能上大致描述了各个层的设计思想。

3)根据设计的文件传输系统的体系框架，对使用到的关键技术的详细设计和实现做出说明，包括系统结构中超级节点的选择，节点问网络的连接以及文件在节点问的传输，并附带部分代码展示了关键技术的实现细节。-P2P technology in the process, many issues to be considered, including network discovery mechanism to share files, data integrity and transmission efficiency and security issues, including network load balancing node problems and so on. In this paper, following the completion of several tasks: 1) based on super-node hybrid P2P network topology, list the common resource locator search algorithm to compare and select the Chord algorithm as the system resource locator search algorithm based, do the improvements.

2) design system framework. P2P applications will have structured into the settings and display the user application layer, with file-sharing mechanism and super-node discovery and selection mechanism to inform the node layer and has a file upload and download functions of the network transport layer. From the general descr iption of each functional layer design.

3) file transfer system according to the design of the system framework, the use of key technologies to achieve the