FTP文件上传和下载文件损坏问题
最近抄了书上的一个FTP的例子，上传和下载是可以了，但是，上传后的文件和下载下来的文件都不能打开，文本倒是可以打开，但是，汉字部分不显示，初学网络编程，希望大侠们指点一二。
例子如下
//服务端using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Drawing;using System.Text;using System.Windows.Forms;using System.Net;using System.Net.Sockets;using System.IO;using System.Threading;using System.Globalization;namespace ftpServer{ public partial class MainForm : Form { TcpListener myTcpListener; Dictionary<string, string> users; public MainForm() { InitializeComponent(); users = new Dictionary<string, string>(); users.Add("mytestName", "123456"); txbDir.Text = "e:/ls/"; } //启动服务 private void btnFTPStart_Click(object sender, EventArgs e) { listBox1.Items.Add("FTP服务已启动"); Thread t = new Thread(ListenClientConnect); t.Start(); btnFTPStart.Enabled = false; btnStop.Enabled = true; } /// <summary> /// 监听端口，处理客户端连接 /// </summary> private void ListenClientConnect() { myTcpListener = new TcpListener(IPAddress.Any, 21); myTcpListener.Start(); while (true) { try { TcpClient client = myTcpListener.AcceptTcpClient(); AddInfo(string.Format("{0}和本机{1}建立FTP连接", client.Client.RemoteEndPoint, myTcpListener.LocalEndpoint)); User user = new User(); user.commandSession = new UserSession(client); user.WorkDir = txbDir.Text; Thread t = new Thread(userProcessing); t.IsBackground = true; t.Start(user); } catch { break; } } } /// <summary> /// 客户连接 /// </summary> /// <param name="user"></param> private void userProcessing(object obj) { User user = (User)obj; string sendString = "220 FTP Server V1.0"; string oldFileName = ""; ReplyCommandToUser(user, sendString); while (true) { string ReceiveString = null; try { ReceiveString = user.commandSession.sr.ReadLine(); } catch { if (user.commandSession.client.Connected == false) { AddInfo("客户端断开连接"); } else { AddInfo("命令接收失败"); } break; } if (ReceiveString == null) { AddInfo("接收字符为null,线程结束"); break; } AddInfo(string.Format("来自[{0}]--{1}", user.commandSession.client.Client.RemoteEndPoint, ReceiveString)); //分解客户端发过来的控制信息中的命令及参数 string command = ReceiveString; string param = string.Empty; int index = ReceiveString.IndexOf(' '); if (index != -1) { command = ReceiveString.Substring(0, index).ToUpper(); param = ReceiveString.Substring(command.Length).Trim(); } //处理不需要登录即可响应的命令(此处仅处理QUIT) if (command == "QUIT") { //关闭TCP连接并释放与其相关的所有资源 user.commandSession.close(); return; } else { switch (user.loginOK) { //等待用户输入用户名 case 0: CommandUser(user, command, param); break; //等待用户输入密码 case 1: CommandPassword(user, command, param); break; //用户名和密码正确时登录 case 2: { switch (command) { case "CWD": CommandCWD(user, param); break; case "PWD": CommandPWD(user);//显示工作目录 break; case "PASV": CommandPASV(user); break; case "PORT": CommandPORT(user, param); break; case "LIST": case "NLIST": CommandLIST(user, param);//显示目录和文件 break; case "RETR": CommandRETR(user, param); break; case "STOR": CommandSTOR(user, param); break; case "TYPE": CommandTYPE(user, param); break; default: sendString = "502 command is not implemented."; ReplyCommandToUser(user, sendString); break; } } break; } } } } /// <summary> /// 处理USER命令，但不进行用户验证 /// </summary> /// <param name="user"></param> /// <param name="command"></param> /// <param name="param"></param> private void CommandUser(User user, string command, string param) { string sendString = string.Empty; if (command == "USER") { sendString = "331 USER command OK,password required."; user.userName = param; user.loginOK = 1;//表示已接收到用户名，等待接收密码 } else { sendString = "501 USER command syntax error."; } ReplyCommandToUser(user, sendString); } /// <summary> /// 输入密码 /// </summary> /// <param name="user"></param> /// <param name="command"></param> /// <param name="param"></param> private void CommandPassword(User user, string command, string param) { string sendString = string.Empty; if (command == "PASS") { string password = null; if (users.TryGetValue(user.userName, out password)) { if (password == param) { sendString = "230 User logged in success"; user.loginOK = 2; //2表示登录成功 } else sendString = "530 Password incorrect."; } else { sendString = "530 User name or password incorrect."; } } else { sendString = "530 PASS command Syntax error."; } ReplyCommandToUser(user, sendString); user.CurrentDir = user.WorkDir; } /// <summary> /// 处理CWD命令，改变工作目录 /// </summary> /// <param name="user"></param> /// <param name="temp"></param> private void CommandCWD(User user, string temp) { string sendString = string.Empty; try { string dir = user.WorkDir.TrimEnd('/') + temp; //是当前目录的子目录，且不包含父目录名称 if (Directory.Exists(dir)) { user.CurrentDir = dir; sendString = "250 Directory changed to '" + dir + "' successfully."; } else { sendString = "550 Directory '" + dir + "' does not exist."; } } catch { sendString = "502 Directory changed unsuccessfully."; } ReplyCommandToUser(user, sendString); }