基于TCPIP聊天软件的代码设计

致得E6协同文档管理系统基于TCP/IP聊天软件的代码设计服务器端开发的详细代码：//添加的命名空间引用(原始生成的略)using ;using .Sockets;using System.Threading;using System.IO;using System.Security.Cryptography;namespace EncryptedTcpServer{public partial class FormServer : Form{//连接的用户System.Collections.Generic.List<User> userList = new List<User>();private delegate void SetListBoxCallback(string str);private SetListBoxCallback setListBoxCallback;private delegate void SetComboBoxCallback(User user);private SetComboBoxCallback setComboBoxCallback;//使用的本机IP地址IPAddress localAddress;//监听端口private int port = 6788;//和书上一样private TcpListener myListener;public FormServer(){InitializeComponent();listBoxStatus.HorizontalScrollbar = true;setListBoxCallback = new SetListBoxCallback(SetListBox);setComboBoxCallback = new SetComboBoxCallback(AddComboBoxitem);IPAddress[] addrIP = Dns.GetHostAddresses(Dns.GetHostName());localAddress = addrIP[0];buttonStop.Enabled = false;}//开始监听private void buttonStart_Click(object sender, EventArgs e){myListener = new TcpListener(localAddress, port);myListener.Start();SetListBox(string.Format("开始在{0}:{1}监听客户连接", localAddress, port));//创建一个线程监听客户端连接请求ThreadStart ts = new ThreadStart(ListenClientConnect);致得E6协同文档管理系统 Thread myThread = new Thread(ts);myThread.Start();buttonStart.Enabled = false;buttonStop.Enabled = true;}//接收客户端连接的线程private void ListenClientConnect(){while (true){TcpClient newClient = null;try{//等待用户进入newClient = myListener.AcceptTcpClient();}catch{//当单击“停止监听”或者退出此窗体时AcceptTcpClient()会产生异常，因此可以利用此异常退出循环break;}//每接受一个客户端连接,就创建一个对应的线程循环接收该客户端发来的信息ParameterizedThreadStart pts = newParameterizedThreadStart(ReceiveData);Thread threadReceive = new Thread(pts);User user = new User(newClient);threadReceive.Start(user);userList.Add(user);AddComboBoxitem(user);SetListBox(string.Format("[{0}]进入",newClient.Client.RemoteEndPoint));SetListBox(string.Format("当前连接用户数：{0}",userList.Count));}}//接收、处理客户端信息的线程，每客户1个线程，参数用于区分是哪个客户private void ReceiveData(object obj){User user = (User)obj;TcpClient client = user.client;致得E6协同文档管理系统 //是否正常退出接收线程bool normalExit = false;//用于控制是否退出循环bool exitWhile = false;while (exitWhile == false){//保存接收的命令字符串string receiveString = null;//每条命令均带有一个参数，值为true或者false，表示是否有紧跟的字节数组string[] splitString = null;byte[] receiveBytes = null;try{//从网络流中读出命令字符串//此方法会自动判断字符串长度前缀，并根据长度前缀读出字符串 receiveString = user.br.ReadString();splitString = receiveString.Split(',');if (splitString[1] == "true"){//先从网络流中读出32位的长度前缀int bytesLength = user.br.ReadInt32();//然后读出指定长度的内容保存到字节数组中receiveBytes = user.br.ReadBytes(bytesLength);}}catch{//底层套接字不存在时会出现异常SetListBox("接收数据失败");}if (receiveString == null){if (normalExit == false){//如果停止了监听，Connected为falseif (client.Connected == true){SetListBox(string.Format("与[{0}]失去联系，已终止接收该用户信息", client.Client.RemoteEndPoint));}致得E6协同文档管理系统 }break;}SetListBox(string.Format("来自[{0}]：{1}",user.client.Client.RemoteEndPoint, receiveString));if (receiveBytes != null){SetListBox(string.Format("来自[{0}]：{1}",user.client.Client.RemoteEndPoint,Encoding.Default.GetString(receiveBytes)));}switch (splitString[0])//公钥和私钥的加密解密实现{case "rsaPublicKey":user.rsa.FromXmlString(Encoding.Default.GetString(receiveBytes));//加密对称加密的私钥try{byte[] encryptedKey = user.rsa.Encrypt(user.tdes.Key, false);SendToClient(user, "tdesKey,true", encryptedKey); //加密IVbyte[] encryptedIV = user.rsa.Encrypt(user.tdes.IV, false);SendToClient(user, "tdesIV,true", encryptedIV);}catch (Exception err){MessageBox.Show(err.Message);}break;case "Logout"://格式：LogoutSetListBox(string.Format("[{0}]退出",user.client.Client.RemoteEndPoint));normalExit = true;exitWhile = true;break;case "Talk"://解密string talkString = DecryptText(receiveBytes,致得E6协同文档管理系统user.tdes.Key, user.tdes.IV);if (talkString != null){SetListBox(string.Format("[{0}]说：{1}",client.Client.RemoteEndPoint, talkString));}break;default:SetListBox("什么意思啊：" + receiveString);break;}}userList.Remove(user);client.Close();SetListBox(string.Format("当前连接用户数：{0}", userList.Count)); }//对称加密算法加密数据的具体实现private byte[] EncryptText(string str, byte[] Key, byte[] IV){//创建一个内存流MemoryStream memoryStream = new MemoryStream();//使用传递的私钥和IV创建加密流CryptoStream cryptoStream = new CryptoStream(memoryStream,new TripleDESCryptoServiceProvider().CreateEncryptor(Key, IV), CryptoStreamMode.Write);//将传递的字符串转换为字节数组byte[] toEncrypt = Encoding.UTF8.GetBytes(str);try{//将字节数组写入加密流,并清除缓冲区cryptoStream.Write(toEncrypt, 0, toEncrypt.Length);cryptoStream.FlushFinalBlock();//得到加密后的字节数组byte[] encryptedBytes = memoryStream.ToArray();return encryptedBytes;}catch (Exception err){SetListBox("加密出错：" + err.Message);return null;}finally致得E6协同文档管理系统 {cryptoStream.Close();memoryStream.Close();}}//使用对称加密算法解密接收的数据private string DecryptText(byte[] dataBytes, byte[] Key, byte[] IV){//根据加密后的字节数组创建一个内存流MemoryStream memoryStream = new MemoryStream(dataBytes);//使用传递的私钥、IV和内存流创建解密流CryptoStream cryptoStream = new CryptoStream(memoryStream,new TripleDESCryptoServiceProvider().CreateDecryptor(Key, IV), CryptoStreamMode.Read);//创建一个字节数组保存解密后的数据byte[] decryptBytes = new byte[dataBytes.Length];try{//从解密流中将解密后的数据读到字节数组中cryptoStream.Read(decryptBytes, 0, decryptBytes.Length);//得到解密后的字符串string decryptedString = Encoding.UTF8.GetString(decryptBytes); return decryptedString;}catch (Exception err){SetListBox("解密出错：" + err.Message);return null;}finally{cryptoStream.Close();memoryStream.Close();}}//发送信息到客户端private void SendToClient(User user, string command, byte[] bytes){//每条命令均带有一个参数，值为true或者false，表示是否有紧跟的字节数组string[] splitCommand = command.Split(',');try致得E6协同文档管理系统 {//先将命令字符串写入网络流，此方法会自动附加字符串长度前缀user.bw.Write(command);SetListBox(string.Format("向[{0}]发送：{1}",user.client.Client.RemoteEndPoint, command));if (splitCommand[1] == "true"){//先将字节数组的长度（32位整数）写入网络流user.bw.Write(bytes.Length);//然后将字节数组写入网络流user.bw.Write(bytes);user.bw.Flush();SetListBox(string.Format("向[{0}]发送：{1}",user.client.Client.RemoteEndPoint,Encoding.UTF8.GetString(bytes)));if (splitCommand[0] == "Talk"){SetListBox("加密前内容：" + textBoxSend.Text);}}}catch{SetListBox(string.Format("向[{0}]发送信息失败",user.client.Client.RemoteEndPoint));}}private void AddComboBoxitem(User user){if (comboBoxReceiver.InvokeRequired == true){this.Invoke(setComboBoxCallback, user);}else{comboBoxReceiver.Items.Add(user.client.Client.RemoteEndPoint); }}private void SetListBox(string str){if (listBoxStatus.InvokeRequired == true){致得E6协同文档管理系统 this.Invoke(setListBoxCallback, str);}else{listBoxStatus.Items.Add(str);listBoxStatus.SelectedIndex = listBoxStatus.Items.Count - 1; listBoxStatus.ClearSelected();}}//单击停止监听按钮触发的事件private void buttonStop_Click(object sender, EventArgs e){SetListBox(string.Format("目前连接用户数：{0}", userList.Count)); SetListBox("开始停止服务，并依次使用户退出!");for (int i = 0; i < userList.Count; i++){comboBoxReceiver.Items.Remove(userList[i].client.Client.RemoteEndPoint);userList[i].bw.Close();userList[i].br.Close();userList[i].client.Close();}//通过停止监听让myListener.AcceptTcpClient()产生异常退出监听线程myListener.Stop();buttonStart.Enabled = true;buttonStop.Enabled = false;}//单击发送按钮的Click事件private void buttonSend_Click(object sender, EventArgs e){int index = comboBoxReceiver.SelectedIndex;if (index == -1){MessageBox.Show("请先选择接收方，然后再单击［发送］");}else{User user = (User)userList[index];//加密textBoxSend.Text的内容byte[] encryptedBytes = EncryptText(textBoxSend.Text,user.tdes.Key, user.tdes.IV);if (encryptedBytes != null)致得E6协同文档管理系统 {SendToClient(user, "Talk,true", encryptedBytes);textBoxSend.Clear();}}}private void FormServer_FormClosing(object sender, FormClosingEventArgs e){//未单击开始监听就直接退出时，myListener为nullif (myListener != null){buttonStop_Click(null, null);}}//textBoxSend获得焦点并释放按键后触发的事件private void textBoxSend_KeyPress(object sender, KeyPressEventArgs e) {if (e.KeyChar == (char)Keys.Return){buttonSend_Click(null, null);}}}}//客户端具体的代码实现略：服务器和客户端的连接实现和教材上的例子具体实现是一样的，就是增加了一个连接时发送共钥和私钥的过程，客户端的加密解密实现原理和服务器端是一样的。