知识大全 P2P的简单示例:VB.net版

Posted 2022-07-17 消息

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这是用实现的一个简单的P P示例利用了UDP打洞技术分服务器端跟客户端服务器端负责登陆记录用户的IP和端口及转发打洞消息 (相关技术在CSDN搜一下有很多的 ) 原理到处都有这里就没有贴出来这里贴出了的代码供初学者交流也欢迎高手点评　　服务器端在启动成功后输入help可以查看到服务器相关命令　　客户端在登陆成功后输入help可以查看客户端相关命令 (登陆时用户名随便 ) 　　以下是服务器端: Imports System Net Imports System Net Sockets Imports System Text Imports System Threading Imports System Collections Module myUDPServer #Region 全局变量 Dim ServerSocket As New Socket(AddressFamily InterNeork SocketType Dgram ProtocolType Udp) Dim ipep As IPEndPoint = New IPEndPoint(IPAddress Any ) Dim htUserList As New Hashtable 用来保存在线用户和用户的 IP和端口 Dim userName( ) As String Dim userIPEP( ) As IPEndPoint Dim userTime( ) As Integer Dim timerDelegate As New TimerCallback(AddressOf onLineTimeOut) #End Region #Region 参数以下是客户端到服务器端的消息开头 Const LOGININ As String = 请求登陆的消息|||消息形式: +自己的用户名 Const LOGINOUT As String = 请求登出的消息|||消息形式: +自己的用户名 Const GETULIST As String = 请求获得在线用户列表|||消息形式: Const P PCONN As String = 请求P P连接的消息|||消息形式: +自己的用户名+|+对方的用户名 Const HOLDLINE As String = 保持连接 |||消息开式: +自己的用户名以下是服务器到客户端的消息开头 Const HVUSER As String = 用户名已存在 Const GETUSER As String = 在线用户列表|||消息格式: +用户名+EP Const MAKHOLD As String = 打洞命令|||消息格式: +IP Const LOGINOK As String = 登陆成功 Const SERVCLS As String = 服务器关闭 Const MSGEND As String = 消息结束以下是服务器端的命名 Const EXITPRO As String = EXIT 退出命令 Const SHOWULIST As String = SHOWUSER 显示在线用户 Const HELP As String = HELP 显示帮助 #End Region #Region 方法主函数程序入口 Sub Main() 获得服务器的IP地址 Dim addressList As System Net IPAddress() = Dns GetHostByName(Dns GetHostName()) AddressList Dim ServerIP As IPAddress = addressList( ) ServerSocket Bind(ipep) Console WriteLine( 服务器正在启动 ) Console WriteLine( 服务器IP: & ServerIP ToString & 正在监听 & ipep Port ToString & 端口 ) Dim listenTH As New Thread(AddressOf listen) listenTH Start() 启用监听的线程 Console WriteLine( 服务器启动成功 ) Dim timer As New Timer(timerDelegate Nothing ) Dim SVInput As String While True Console Write( Server> ) SVInput = Console ReadLine() ToUpper Select Case SVInput Case EXITPRO listenTH Abort() ServerSocket Close() Exit Sub Case SHOWULIST showUser() Case HELP Console Write( ********************************* & Chr( ) & Chr( ) & exit:输出当前程序 & Chr( ) & Chr( ) & showuser:显示当前在线用户例表 & Chr( ) & Chr( ) & help:显示帮助 & Chr( ) & Chr( ) & ********************************* & Chr( ) & Chr( )) Case Else Console WriteLine( ********************************* & Chr( ) & Chr( ) & 笨瓜你输入的不是有效的命令 & Chr( ) & Chr( ) & ********************************* ) End Select End While End Sub 打印在线用户 Sub showUser() Dim hava As Boolean = False If userName Length <> Then Dim i As Integer For i = To userName Length If userName(i) <> Then hava = True Exit For End If Next If hava = False Then Console WriteLine( ********************************* & Chr( ) & Chr( ) & 当前没有用户在线 & Chr( ) & Chr( ) & ********************************* ) Exit Sub End If Console WriteLine( ********************************* ) For i = To userName Length If userName(i) <> Then Console WriteLine( 用户名: & userName(i) & 地址: & userIPEP(i) ToString) End If Next Console WriteLine( ********************************* ) Else Console WriteLine( ********************************* & Chr( ) & Chr( ) & 当前没有用户在线 & Chr( ) & Chr( ) & ********************************* ) End If End Sub 服务器监听函数 Sub listen() While True Try Dim recv As Integer = Dim data As [Byte]() = New Byte( ) Dim sender As New IPEndPoint(IPAddress Any ) Dim tempRemoteEP As EndPoint = CType(sender EndPoint) recv = ServerSocket ReceiveFrom(data tempRemoteEP) Console WriteLine(Encoding Unicode GetString(data)) Dim msgHead As String = Encoding Unicode GetString(data ) Select Case msgHead Case LOGININ Dim LoginThing As String = userLogin(data tempRemoteEP recv) If LoginThing = HVUSER Then sendMsg(HVUSER tempRemoteEP) ElseIf LoginThing = LOGINOK Then sendMsg(LOGINOK tempRemoteEP) End If Case LOGINOUT userloginout(data recv) Case GETULIST Dim userinfo As String = getUserList() sendMsg(userinfo tempRemoteEP) Case P PCONN questP PConn(data recv) Case HOLDLINE holdOnLine(data recv) End Select Catch e As Exception Console WriteLine(e ToString) End Try End While End Sub 转发P P连接请求 Private Sub questP PConn(ByVal data() As Byte ByVal recv As Integer) Dim recvStr As String = Encoding Unicode GetString(data recv ) Dim split() As String = recvStr Split( | ) Dim fromEP As IPEndPoint Dim toEP As IPEndPoint Dim i As Integer For i = To userName Length If userName(i) = split( ) Then fromEP = userIPEP(i) End If If userName(i) = split( ) Then toEP = userIPEP(i) End If Next Dim holdbytes() As Byte = Encoding Unicode GetBytes(MAKHOLD & fromEP ToString) ServerSocket SendTo(holdbytes toEP) End Sub 函数返回所有在线用户其格式:用户名+|+用户IPEP+| Private Function getUserList() As String Dim userInfo As String = GETUSER Dim i As Integer For i = To userName Length If userName(i) <> Then userInfo += userName(i) & | & userIPEP(i) ToString & | End If Next Return userInfo End Function 用户登陆直接返回登陆是否成功的值 Private Function userLogin(ByVal data As Byte() ByVal userEP As IPEndPoint ByVal recvCount As Integer) As String Dim Uname As String = Encoding Unicode GetString(data recvCount ) Dim Uinfobytes() As Byte Dim i As Integer Dim j As Integer For i = To userName Length If Uname = userName(i) Then Return HVUSER End If Next For i = To userName Length If userName(i) = Then userName(i) = Uname userIPEP(i) = userEP userTime(i) = Console Write(Chr( ) & Chr( ) & ********************************* & Chr( ) & Chr( ) & Uname Trim & 上线了 & 用户地址: & userEP ToString & Chr( ) & Chr( ) & ********************************* & Chr( ) & Chr( )) Console Write( Server> ) Uinfobytes = Encoding Unicode GetBytes(LOGININ & userName(i) & | & userIPEP(i) ToString) For j = To userName Length If userName(j) <> And userName(j) <> Uname Then ServerSocket SendTo(Uinfobytes userIPEP(j)) End If Next Return LOGINOK End If Next Dim userCount As Integer = userName Length ReDim Preserve userName(userCount) ReDim Preserve userIPEP(userCount) ReDim Preserve userTime(userCount) userName(userName Length ) = Uname userIPEP(userIPEP Length ) = userEP userTime(userTime Length ) = Console Write(Chr( ) & Chr( ) & ********************************* & Chr( ) & Chr( ) & Uname Trim & 上线了 & 用户地址: & userEP ToString & Chr( ) & Chr( ) & ********************************* & Chr( ) & Chr( )) Console Write( Server> ) Uinfobytes = Encoding Unicode GetBytes(LOGININ & userName(userName Length ) & | & userIPEP(userName Length ) ToString) For j = To userName Length If userName(j) <> And userName(j) <> Uname Then ServerSocket SendTo(Uinfobytes userIPEP(j)) End If Next Return LOGINOK End Function 用户登出 Private Sub userloginout(ByVal data As Byte() ByVal recvCount As Integer) Dim i As Integer Dim Uname As String = Encoding Unicode GetString(data recvCount ) For i = To userName Length If Uname = userName(i) Then Dim loginOutMsg As String = LOGINOUT & userName(i) userName(i) = userIPEP(i) = Nothing userTime(i) = Dim j As Integer For j = To userName Length If userName(j) <> Then sendMsg(loginOutMsg userIPEP(j)) End If Next Console WriteLine(Chr( ) & Chr( ) & ********************************* ) Console WriteLine( 用户 & Uname & 下线了 ) Console WriteLine( ********************************* ) Console Write( Server> ) Exit For End If Next End Sub 保持用户在线的过程 Private Sub holdOnLine(ByVal data As Byte() ByVal recvCount As Integer) Dim Uname As String = Encoding Unicode GetString(data recvCount ) Dim i As Integer For i = To userName Length If Uname = userName(i) Then userTime(i) = Exit For End If Next End Sub 用户超时退出 Private Sub onLineTimeOut(ByVal state As [Object]) Dim i As Integer For i = To userName Length If userTime(i) > Then userTime(i) = If userTime(i) <= Then Dim loginoutmsg As String = LOGINOUT & userName(i) Console WriteLine(Chr( ) & Chr( ) & ********************************* ) Console WriteLine( 用户 & userName(i) & 下线了 ) Console WriteLine( ********************************* ) Console Write( Server> ) userName(i) = userIPEP(i) = Nothing Dim ULoginOutbytes() As Byte = Encoding Unicode GetBytes(loginoutmsg) Dim j As Integer For j = To userName Length If userName(j) <> Then If userIPEP(j) Is Nothing Then Else ServerSocket SendTo(ULoginOutbytes userIPEP(j)) End If End If Next End If End If Next End Sub 发送消息的函数 Sub sendMsg(ByVal msg As String ByVal remoteEP As IPEndPoint) Dim sendBytes As [Byte]() = Encoding Unicode GetBytes(msg) Try ServerSocket SendTo(sendBytes remoteEP) Catch e As Exception Console WriteLine(e ToString()) End Try End Sub #End Region End Module 以下是客户端: Imports System Net Imports System Net Sockets Imports System Text Imports System Threading Module Module #Region 参数以下是客户端到服务器端的消息开头 Const LOGININ As String = 请求登陆的消息|||消息形式: +自己的用户名 Const LOGINOUT As String = 请求登出的消息|||消息形式: +自己的用户名 Const GETULIST As String = 请求获得在线用户列表|||消息形式: +自己的用户名 Const P PCONN As String = 请求P P连接的消息|||消息形式: +自己的用户名+对方的用户名 Const HOLDLINE As String = 保持连接 |||消息开式: +自己的用户名以下是服务器到客户端的消息开头 Const HVUSER As String = 用户名已存在 Const GETUSER As String = 在线用户列表|||消息格式: +用户名+EP Const MAKHOLD As String = 打洞命令|||消息格式: +IP Const LOGINOK As String = 登陆成功 Const SERVCLS As String = 服务器关闭 Const MSGEND As String = 消息结束以下是客户端到客户端的消息开头 Const HOLDOK As String = 打洞成功 Const CHATMSG As String = 聊天消息 Const CHTMSGEND As String = 聊天消息发送成功以下是客户端的命名 Const EXITPRO As String = EXIT 退出命令 Const SHOWULIST As String = SHOWUSER 显示在线用户 Const HELP As String = HELP 显示帮助 Const SEND As String = SEND 发送消息 #End Region #Region 全局全量 Delegate Sub myMethodDelegate(ByRef myInData As Byte()) 登陆时用的事件 Dim MaxTry As Integer = Dim msgSendEnd As Boolean = False 消息是否发送成功若发送成功则会返回结束消息 Dim ThListen As New Thread(AddressOf listen) 监听的线程 Dim ClientSocket As New Socket(AddressFamily InterNeork SocketType Dgram ProtocolType Udp) 客户端套节字的定义 Dim username As String 当前用户名 Dim ServerEP As IPEndPoint 服务器的IPEP Dim holdBytes As [Byte]() = Encoding Unicode GetBytes(HOLDLINE & username) 和服务器保持连接连接时用到的byte数组 Dim OLUserName() As String Dim OLUserEP() As IPEndPoint Dim getUrecCount As Integer Dim testHold As Boolean = False Dim testChat As Boolean = False Private receiveDone As ManualResetEvent 在登陆时用来阻塞线程等待收到数据 Private sendDone As ManualResetEvent 用来阴塞发送消息的线程等待收到回送的确认消息 Private getUDone As ManualResetEvent 用来阻塞请求好友名单的线程等待接收好友名单 Private holdDone As ManualResetEvent 用来阻塞打洞时的线程 Private chatDone As ManualResetEvent 用来阻塞发送聊天消息时的线程 Dim timerDelegate As New TimerCallback(AddressOf holdonline) 为保持在线状态弄得 #End Region #Region 方法主函数程序入口 Sub Main() Dim InputIP As String Dim InputOK As Boolean = False 判断输入的IP 并且保存服务器的IPEP While InputOK <> True Console Write( 请输入服务器IP: ) InputIP = Console ReadLine() Try ServerEP = New IPEndPoint(IPAddress Parse(InputIP) ) InputOK = True Catch Console WriteLine( 你输入的服务器IP不正确请重新输入 ) InputOK = False End Try End While Dim bool As Boolean = False 判断用户是否登陆成功 While bool <> True Dim LoginOK As Boolean = Login() If LoginOK = True Then bool = True Else Console Write( 是否重试:输入Y重试输入任意值退出程序: ) Dim tempYN As String = Console ReadLine ToUpper If tempYN = Y Then bool = False Else Exit Sub End If End If End While Console WriteLine( 用户名: & username) holdBytes = Encoding Unicode GetBytes(HOLDLINE & username) 登陆成功后用一个timer 每隔秒向服务器发送消息保持在线状态跟在主机注册的端口 Dim timer As New Timer(timerDelegate Nothing ) 请求在线名单 Console WriteLine( 正在获取在线名单请稍后 ) Dim getUbool As Boolean = False While getUbool <> True getUbool = getU() If getUbool = False Then Console Write( 是否重试:输入Y重试输入任意值退出程序: ) Dim tempYN As String = Console ReadLine ToUpper If tempYN = Y Then bool = False Else Exit Sub End If End If End While ThListen Start() 用来处理客户端的一些命令 Dim SVInput As String While True Console Write( Client> ) SVInput = Console ReadLine() ToUpper Select Case SVInput Case EXITPRO exitApp() ThListen Abort() ClientSocket Close() Exit Sub Case SHOWULIST Console WriteLine( ********************************* ) showUserList() Console WriteLine( ********************************* ) Case HELP Console Write( ********************************* & Chr( ) & Chr( ) & exit:输出当前程序 & Chr( ) & Chr( ) & showuser:显示当前在线用户例表 & Chr( ) & Chr( ) & send:发送消息格式:send 用户名消息 & Chr( ) & Chr( ) & help:显示帮助 & Chr( ) & Chr( ) & ********************************* & Chr( ) & Chr( )) Case Else If SVInput Substring( ) = SEND Then Dim split() As String = SVInput Split( ) If split Length = Then sendChatMsg(split( ) split( )) Else Console WriteLine( ********************************* & Chr( ) & Chr( ) & 你输入的命令格式不正确 send命令格式为:send 用户名你的消息 & Chr( ) & Chr( ) & ********************************* ) End If Else Console WriteLine( ********************************* & Chr( ) & Chr( ) & 笨瓜你输入的不是有效的命令 & Chr( ) & Chr( ) & ********************************* ) End If End Select End While End Sub 登陆函数 Private Function Login() As Boolean receiveDone = New ManualResetEvent(False) Dim userBytes As [Byte]() Dim userOK As Boolean = False Console Write( 请输入你的用户名: ) 判断用户名是否符合格式 While (userOK <> True) username = Console ReadLine ToUpper userBytes = Encoding Unicode GetBytes(LOGININ & username) If userBytes Length > Or userBytes Length < Then Console WriteLine( 用户名不得小于个字节且不得大于个字节 ) Console Write( 请重新输入你的用户名: ) Else userOK = True End If End While 向服务器发送客户消息 ClientSocket SendTo(userBytes ServerEP) Dim data As [Byte]() = New Byte( ) Dim Str As String = Encoding Unicode GetString(data ) 异面的接收服务器回送的消息 Dim DGrecv As New myMethodDelegate(AddressOf recvLogin) DGrecv BeginInvoke(data Nothing Nothing) 等待服务器回送消息的时长为秒否则为服务器超时 receiveDone WaitOne( True) Dim recvStr As String = Encoding Unicode GetString(data ) If recvStr = Str Then Console WriteLine( 服务器超时登陆失败!! ) Return False End If If Encoding Unicode GetString(data ) = LOGINOK Then Console WriteLine( 登陆成功!! ) Return True ElseIf Encoding Unicode GetString(data ) = HVUSER Then Console WriteLine( 用户名重复登陆失败!! ) Return False Else Console WriteLine( 服务器未知错误登陆失败!! ) Return False End If End Function 登出函数 Private Sub exitApp() Dim loginOutStr As String = LOGINOUT & username Dim sendBytes As [Byte]() = Encoding Unicode GetBytes(loginOutStr) ClientSocket SendTo(sendBytes ServerEP) End Sub 请求好友列表的函数 Private Function getU() As Boolean getUDone = New ManualResetEvent(False) Dim getUbytes As Byte() = Encoding Unicode GetBytes(GETULIST) ClientSocket SendTo(getUbytes ServerEP) Dim data As [Byte]() = New Byte( ) Dim Str As String = Encoding Unicode GetString(data ) Dim GUrecv As New myMethodDelegate(AddressOf recvGetU) GUrecv BeginInvoke(data Nothing Nothing) getUDone WaitOne( True) Dim recvStr As String = Encoding Unicode GetString(data ) If recvStr = Str Then Console WriteLine( 服务器超时或取好友名单失败!! ) Return False End If If Encoding Unicode GetString(data ) = GETUSER Then getUserList(data getUrecCount) Console WriteLine( 获取在线名单成功!! ) showUserList() Return True Else Console WriteLine( 服务器未知错误获取在线名单失败!! ) Return False End If End Function 登陆时用来异步的接收服务器发送的消息 Sub recvLogin(ByRef inData As Byte()) ClientSocket Receive(inData) receiveDone Set() End Sub 请求好友名单时用来异步接收服务器发送的消息 Sub recvGetU(ByRef inData As Byte()) getUrecCount = ClientSocket Receive(inData) getUDone Set() End Sub 处理收到的在线用户信息 Private Sub getUserList(ByVal userInfobytes() As Byte ByVal reccount As Integer) Dim ustr As String = Encoding Unicode GetString(userInfobytes reccount ) Dim splitStr() As String = Nothing splitStr = Ustr Split( | ) Dim IPEPSplit() As String = Nothing Dim i As Integer = Dim k As Integer For k = To splitStr Length Step ReDim Preserve OLUserName(i) ReDim Preserve OLUserEP(i) OLUserName(i) = splitStr(k) IPEPSplit = splitStr(k + ) Split( : ) OLUserEP(i) = New IPEndPoint(IPAddress Parse(IPEPSplit( )) IPEPSplit( )) IPEPSplit = Nothing i += Next End Sub 显示在线用户 Private Sub showUserList() Dim i As Integer For i = To OLUserName Length If OLUserName(i) <> Then Console WriteLine( 用户名: & OLUserName(i) & 用户IP: & OLUserEP(i) ToString) End If Next End Sub 客户程序监听的函数 Sub listen() While True Try Dim recv As Integer = 收到的字节数 Dim data As [Byte]() = New Byte( ) 缓冲区大小 Dim sender As New IPEndPoint(IPAddress Any ) Dim tempRemoteEP As EndPoint = CType(sender EndPoint) recv = ClientSocket ReceiveFrom(data tempRemoteEP) Dim msgHead As String = Encoding Unicode GetString(data ) 获得消息头的内容 Select Case msgHead Case MSGEND msgSendEnd = True sendDone Set() Case LOGININ addOnLine(data recv) Case LOGINOUT removeOnLine(data recv) Case MSGEND msgSendEnd = True sendDone Set() Case MAKHOLD Console WriteLine(Chr( ) & Chr( ) & 收到打洞消息 ) makeHold(data recv) Console Write( Client> ) Case CHATMSG showChatMsg(data recv) Case HOLDOK testHold = True holdDone Set() Case CHTMSGEND testChat = True chatDone Set() End Select Catch End Try End While End Sub 发送聊天消息 Private Sub sendChatMsg(ByVal remoteUser As String ByVal chatMsgStr As String) If remoteUser = username Then Console WriteLine( 猪头你想干什么!!! ) Exit Sub End If Dim i As Integer Dim remoteUEP As IPEndPoint For i = To OLUserName Length If remoteUser = OLUserName(i) Then remoteUEP = OLUserEP(i) Exit For End If If i = OLUserName Length Then Console WriteLine( 找不到你想发送的用户 ) Exit Sub End If Next Dim msgbytes() As Byte = Encoding Unicode GetBytes(CHATMSG & username & | & chatMsgStr) Dim holdbytes() As Byte = Encoding Unicode GetBytes(P PCONN & username & | & remoteUser) chatDone = New ManualResetEvent(False) ClientSocket SendTo(msgbytes remoteUEP) chatDone WaitOne( True) If testChat = True Then testChat = False Exit Sub End If testHold = False While testHold <> True Console WriteLine( 打洞ing ) holdDone = New ManualResetEvent(False) ClientSocket SendTo(holdbytes remoteUEP) ClientSocket SendTo(holdbytes ServerEP) holdDone WaitOne( True) If testHold = True Then Exit While Else Console WriteLine( 打洞超时发送消息失败 ) Console Write( 是否重试按Y重试按任意值结束发送: ) Dim YorN As String = Console ReadLine() ToUpper If YorN = Y Then testHold = False Else Exit Sub End If End If End While While testChat <> True Console WriteLine( 打洞成功正在准备发送 ) chatDone = New ManualResetEvent(False) ClientSocket SendTo(msgbytes remoteUEP) chatDone WaitOne( True) If testChat = True Then Console WriteLine( 消息发送成功!! ) Exit While Else Console WriteLine( 发送超时发送消息失败 ) Console Write( 是否重试按Y重试按任意值结束发送: ) Dim YorN As String = Console ReadLine() ToUpper If YorN = Y Then testChat = False Else Exit Sub End If End If End While testHold = False testChat = False End Sub 处理聊天消息 Private Sub showChatMsg(ByVal indata() As Byte ByVal recvcount As Integer) Dim msgStr As String = Encoding Unicode GetString(indata recvcount ) Dim splitStr() As String = msgStr Split( | ) Dim fromUname As String = splitStr( ) Dim msg As String = splitStr( ) Console WriteLine(Chr( ) & Chr( ) & 收到来自 & fromUname & 的消息: & msg) Console Write( Client> ) Dim i As Integer For i = To OLUserName Length If OLUserName(i) = fromUname Then Exit For End If Next Dim tempbytes() As Byte = Encoding Unicode GetBytes(CHTMSGEND) ClientSocket SendTo(tempbytes OLUserEP(i)) End Sub 处理打洞函数 Private Sub makeHold(ByVal indata() As Byte ByVal recvcount As Integer) Dim makholdstr As String = Encoding Unicode GetString(indata recvcount) Dim ipepstr() As String = makholdstr Split( : ) Dim holdEP As IPEndPoint = New IPEndPoint(IPAddress Parse(ipepstr( )) ipepstr( )) Dim holdbytes() As Byte = Encoding Unicode GetBytes(HOLDOK & username) ClientSocket SendTo(holdbytes holdEP) Console WriteLine( 回送打洞消息 ) End Sub 处理用户上线的函数 Private Sub addOnLine(ByVal inData() As Byte ByVal recvCount As Integer) Dim inStr As String = Encoding Unicode GetString(inData recvCount ) Dim userinfo() As String = inStr Split( | ) Dim strUserEP() As String = userinfo( ) Split( : ) Dim i As Integer For i = To OLUserName Length If OLUserName(i) = Then OLUserName(i) = userinfo( ) OLUserEP(i) = New IPEndPoint(IPAddress Parse(strUserEP( )) strUserEP( )) Console WriteLine(Chr( ) & Chr( ) & 用户 & OLUserName(i) & 上线了用户地址: & OLUserEP(i) ToString) Console Write( Client> ) Exit Sub End If Next ReDim Preserve OLUserName(i + ) ReDim Preserve OLUserEP(i + ) OLUserName(i + ) = userinfo( ) OLUserEP(i + ) = New IPEndPoint(IPAddress Parse(strUserEP( )) strUserEP( )) Console WriteLine(Chr( ) & Chr( ) & 用户 & OLUserName(i + ) & 上线了用户地址: & OLUserEP(i + ) ToString) Console Write( Client> ) End Sub 处理用户下线的函数 Private Sub removeOnLine(ByVal inData() As Byte ByVal recvCount As Integer) Dim offUname As String = Encoding Unicode GetString(inData recvCount ) Dim i As Integer For i = To OLUserName Length If OLUserName(i) = offUname Then OLUserName(i) = OLUserEP(i) = Nothing Console WriteLine(Chr( ) & Chr( ) & 用户 & offUname & 下线了 ) Console Write( Client> ) Exit Sub End If Next End Sub 发送消息的函数 Public Function sendmsg(ByVal msg As String ByVal sendToIPEP As IPEndPoint) As String Dim sendBytes As [Byte]() = Encoding Unicode GetBytes(msg) 判断发送的字节数是否超过了服务器缓冲区大小 If sendBytes Length > Then Return W输入的字数太多 End If 判断消息是否发送成功 While msgSendEnd = False sendDone = New ManualResetEvent(False) Try ClientSocket SendTo(sendBytes sendToIPEP) sendDone WaitOne( True) 阻塞线程秒 If msgSendEnd = False Then Console WriteLine( 消息发送超时 ) Else Exit While End If Catch e As Exception Console WriteLine( 发送消息失败 & e ToString) Exit Function End Try Console Write( 是否重试?按Y重试按任意键退出: ) Dim userInput As String = Console ReadLine ToUpper If userInput = Y Then Else msgSendEnd = False Exit Function End If End While msgSendEnd = False End Function 用保持在线状态的函数 Private Sub holdonline(ByVal state As [Object]) ClientSocket SendTo(holdBytes ServerEP) End Sub #End Region End Module cha138/Article/program/net/201311/13617