计算机网络课程设计报告（FTP客户端的设计与实现）

FTP客户端的设计与实现

课程设计报告

课程名称： 计算机网络

设计题目： FTP客户端的设计与实现

系 别： 计算机与信息工程学院

专 业： 计算机科学与技术 组 别： 第一组 起止日期: 2011年11月25 日~ 2011年12月10日 指导教师:

计算机科学与技术系二○一 一年制

FTP客户端的设计与实现

课程设计任务书

课程设计题目 组长 系别 组员 计算机与信息工程学院 指导教师 课程设计目的 课程设计所需环境 根据FTP协议的工作原理，实现一个FTP的客户端程序 开发环境：JCreator Pro 运行环境：Windows操作系统 (1) 根据账号和密码登录指定的FTP服务器； 课程设计任务要求 (2) 能够查看服务器内容列表，重命名或删除指定的文件/文件夹； (3) 上传或下载选定的文件到服务器上。 课程设计工作进度计划 序号 1 2 3 4 5 6 指导教师签字： 年 月 日 教研室审核意见： 教研室主任签字： 年 月 日

起止日期 2011-11-25至2011-11-28 2011-11-29至2011-12-5 2011-12-2至2011-12-6 2011-12-5至2011-12-8 2011-12-5至2011-12-8 2011-12-7至2011-12-9 工 作 内 容 明确设计目的，网上、图书馆搜查资料 分工情况 小组成员共同参与 FTP客户端的设计与实现 学号 专业 2011220081 计算机科学与技术 班级 计专112班 界面设计，连接服务器， 获取文件列表，断开连接 上传文件、下载文件 删除、重命名文件及刷新列表 返回上级目录，查看日志信息 最后整合测试修改 由 由 由 由 第 1 页 共 27 页

FTP客户端的设计与实现

目 录

第一章 序言 ················································································································· 3

1.1课题来源 ························································································································· 3 1.2开发工具 ························································································································· 3

第二章 系统需求分析 ······························································································· 5

2.1功能需求 ························································································································· 5 2.2 系统模型设计 ················································································································ 5 2.3 系统工作流程设计 ········································································································ 5

第三章 系统设计 ········································································································· 7

3.1实现功能 ························································································································· 7 3.2函数说明 ························································································································· 7

3.2.1界面设计代码 ··················································································································· 7 3.2.2功能实现函数 ················································································································· 11

第四章 系统实现 ······································································································· 13

4.1界面设计的实现 ··········································································································· 13 4.1.1连接服务器 ······················································································································ 14 4.1.2获取文件列表 ················································································································· 14 4.1.3断开服务器 ······················································································································ 15 4.1.4上传文件 ·························································································································· 16 4.1.5下载 ··································································································································· 17

4.1.6重命名 ··································································································································· 19 4.1.7删除 ······································································································································· 20 4.1.8刷新 ······································································································································· 22 4.1.9返回上一目录 ······················································································································· 22 4.1.10查看日志信息 ····················································································································· 23

第五章 总结 ··············································································································· 24 第六章 参考文献 ······································································································· 24

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FTP客户端的设计与实现

第一章 序言

——耿桂花

1.1课题来源

FTP（File Transfer Protocol, FTP）是TCP/IP网络上两台计算机传送文件的协议，FTP是在TCP/IP网络和INTERNET上最早使用的协议之一，它属于网络协议组的应用层。FTP客户机可以给服务器发出命令来下载文件，上载文件，创建或改变服务器上的目录。FTP是一个8位的客户端-服务器协议，能操作任何类型的文件而不需要进一步处理，就像MIME或Unencode一样。但是，FTP有着极高的延时，这意味着，从开始请求到第一次接收需求数据之间的时间会非常长，并且不时的必需执行一些冗长的登陆进程。FTP服务一般运行在20和21两个端口。端口20用于在客户端和服务器之间传输数据流，而端口21用于传输控制流，并且是命令通向ftp服务器的进口。当数据通过数据流传输时，控制流处于空闲状态。而当控制流空闲很长时间后，客户端的防火墙会将其会话置为超时，这样当大量数据通过防火墙时，会产生一些问题。此时，虽然文件可以成功的传输，但因为控制会话会被防火墙断开，传输会产生一些错误。FTP客户端主要目标是：促进文件的共享（计算机程序或数据）；鼓励间接或者隐式的使用远程计算机；向用户屏蔽不同主机中各种文件存储系统的细节；可靠和高效的传输数据。

因此，开发FTP客户端成为一个很有必要的事情。

1.2开发工具

随着程序设计技术的改革和计算机环境的改变，Java语言也得到了迅速发展。一方面，C++等面向对象程序设计语言的发展为Java提供了基础。事实上，Java也大量继承了C以及C++的成果，并增加了体现程序设计发展状态的功能。另一方面，网络及Internet的发展对程序设计提出了新的要求，为Java的发展注入了强大的动力。正是Internet的快速发展和普及，改变了传统的计算模式，促进了Java的普及与流行。

它最初被命名为Oak，目标设定在家用电器等小型系统的编程语言，来解决诸如电视机、电话、闹钟、烤面包机等家用电器的控制和通讯问题。由于这些智能化家电的市场需求没有预期的高，Sun放弃了该项计划。就在Oak几近失败之时，随着互联网的发展，Sun看到了Oak在计算机网络上的广阔应用前景，于是改造了Oak，以“Java”的名称正式发布。

Java 编程语言的风格十分接近C、C++语言。Java是一个纯的面向对象的程序设计语言，它继承了 C++ 语言面向对象技术的核心，Java舍弃了C ++语言中容易引起错误的指针（以引用取代）、运算符重载（operator overloading）、多重继承（以接口取代）等特性，增加了垃圾回收器功能用于回收不再被引用的对象所

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