The Realization Of Proxy Server Bbase On HTTP And Research On Cache Replacement Algorithm

With the development of computer technology and the popularity of Internet, people depend on the network has penetrated into all areas of daily life, networking activities such as online shopping, video chat, searching for information and so on, make people maintain close contact with the network at any time, not only bring convenient to people's lives, but also make people's lives more colorful. However, while the rapid development of network, network management is bringing new issues to people, network security, the limited IP addresses, network traffic and web access latency became the focus of attention, because they affect the sustainable development of the network. Proxy server is considered to be an effective method of solving the problem, and it is a method that people often use at present, and became a research focus of many researchers.Proxy server is a server which is between the client and Web server, when the network users to access information on the Internet, it represents the user access to network information. When the client sends a request to the server, the request is first sent to the proxy server, and then the proxy server analyzes the received request, and to see if there is the request data in the proxy cache. If there is, the proxy server directly passes the request data to the client. Otherwise, the proxy server sends a request to the server in the same way as client request, and transfers the data that accessed from the server to the client. In the same time, retaining the copy of the data in the proxy cache, so, when the client sends the same request, it can directly access the data from the proxy server, without having to send the request to the server.The emergence of agent technology makes all internal network users access the outside world through a proxy server with only one IP address, and outsiders can not directly access to the internal network, which played a role in isolation. At the same time, by setting the appropriate access rules, the proxy server can be used to restrict internal network to external access, and effectively resist the invasion of insecure information outside.The emergence of agent technology enable all internal network use only occupy one IP when access to the outside world, therefore, saving the cost of IP to some extent, and also reducing the cost of access, lowering costs for maintenance of the network. In addition, in the information transfer process, the proxy server has played a buffer role, not only can save network bandwidth, but also increased access speed.Based on this background, this paper implemented a simple proxy server using JAVA based on HTTP protocol, and studied and researched of the cache replacement algorithm systematic, and designed a simulation program, in order to study the performance parameters of the replacement algorithm, and improved the traditional algorithms, and gave a better algorithm.In the process of studying and designing of the system, the main work is as follows:(1) Systematic studied and researched the relevant theoretical knowledge of proxy server and cache replacement algorithm.(2) Implemented a simple proxy server using JAVA based on HTTP protocol.(3) Through studying and analyzing on some typical cache replacement algorithm, this paper gave the first and second improvement based on the Hybrid algorithm, and designed a simulation program, and compared with some typical algorithms from the URL hit rate, byte hit rate and delay rate.The experimental results showed that, in the same simulation of the URL string input shed, maintaining a relatively low latency rate and relatively high URL hit rate, the byte hit ratio of the improved algorithm was greatly improved, and reduced the network traffic, which had a certain significance in improving network conditions.