UDP文件传输问题

本文介绍了UDP文件传输问题的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述 29岁程序员，3月因学历无情被辞！ 我正在尝试创建一个点对点应用程序来发送文件，然后我将大文件分成小块。我首先发送文件信息，包括文本格式的文件信息，没有问题，但发送字节在客户端的某些时刻停止，我把它放在标有BOLD的代码片段中。我不知道数据包是丢失还是代码不同步。这是两个类的代码片段，这里是我从客户端读取文件的代码 提前感谢 class DownloadClientHi, I am trying to create a peer to peer application to send files , then I divide big files to small chunks.  I send first the file information including name and size in text format with no problems but sending bytes stops at certain moments from the client side , I have it down in the code snippet marked in BOLD. I don't know if the packets are lost or if the code is not synchronized. Here is the code snippets for both classes ,here is the code I am doing to read the file from the clientThanks in advanceclass DownloadClient { private const int MAX_BUFFER_SIZE = 10240;private const int MAX_BUFFER_SIZE = 10240; Byte [] inputToBeSent = new Byte [256];Byte[] inputToBeSent = new Byte[256]; UdpClient udpClient;UdpClient udpClient; IPEndPoint remoteIpEndPoint;IPEndPoint remoteIpEndPoint; IPHostEntry remoteHostEntry;IPHostEntry remoteHostEntry; Socket DownloadSocket;Socket DownloadSocket; public int sendLine（ string line）public int sendLine(string line) { inputToBeSent = System.Text。 编码 .ASCII.GetBytes（line.ToCharArray（））;inputToBeSent = System.Text.Encoding.ASCII.GetBytes(line.ToCharArray()); int nBytesSent = udpClient.Send（inputToBeSent，inputToBeSent.Length）;int nBytesSent = udpClient.Send(inputToBeSent, inputToBeSent.Length); return nBytesSent;return nBytesSent;} public void sendBytes（ byte [] data）public void sendBytes(byte[] data) { udpClient.Send（data，data.Length）;udpClient.Send(data, data.Length);} public byte [] Receive（）public byte[] Receive() { byte [] buf = new byte [14];byte[] buf = new byte[14]; buf = udpClient.Receive（ ref remoteIpEndPoint）;buf = udpClient.Receive(ref remoteIpEndPoint); return buf;return buf;} public string ReceiveLine（）public string ReceiveLine() { return System.Text。 编码 .ASCII.GetString（Receive（））;return System.Text.Encoding.ASCII.GetString(Receive());} public void Connect（ string remoteUserIP， int _remoteUserPort）public void Connect(string remoteUserIP, int _remoteUserPort) { udpClient = new UdpClient （）;udpClient = new UdpClient(); udpClient.Connect（ IPAddress 。解析（ " 127.0.0.1" ），9050）;udpClient.Connect(IPAddress.Parse("127.0.0.1"), 9050); // MessageBox.Show （files.Length.ToString（））;// MessageBox.Show(files.Length.ToString()); 的 // for（int i = 0;我< files.Length; i ++）//for (int i = 0; i < files.Length; i++) // {//{ string fileName = "EG7.pdf" ;string fileName = "EG7.pdf"; DownloadSocket.Send（ 编码 .ASCII.GetBytes（ " getFile＃" + " user" + "＃" + fileName））;DownloadSocket.Send(Encoding.ASCII.GetBytes("getFile#" + "user" + "#" + fileName)); // sendLine（" getFile＃" +" user" +& QUOT;＃" + fileName）;//sendLine("getFile#" + "user" + "#" + fileName); // string tmp = ReceiveLine（）;//string tmp = ReceiveLine(); Byte [] received = new 字节 [512];Byte[] received = new Byte[512]; String tmp = ReceiveLine（）;String tmp = ReceiveLine(); if （tmp.StartsWith（ "错误" ））if (tmp.StartsWith("Error")) { int downloaded = 0;int downloaded = 0; int read = 0; int read = 0; byte [] stream = null ;byte[] stream = null; 尝试try { while （已下载< nbBytes）while (downloaded < nbBytes) { if （nbBytes - 已下载> MAX_BUFFER_SIZE）if (nbBytes - downloaded > MAX_BUFFER_SIZE) { stream = new byte [MAX_BUFFER_SIZE];stream = new byte[MAX_BUFFER_SIZE];} elseelse { stream = new byte [nbBytes - 已下载];stream = new byte[nbBytes - downloaded];}已下载+ = udpClient.Available;downloaded += udpClient.Available; stream = udpClient.Receive（ ref remoteIpEndPoint） ;stream = udpClient.Receive(ref remoteIpEndPoint);}} catch （ 例外 e）catch (Exception e) { MessageBox .Show（e.Message）;MessageBox.Show(e.Message);} MessageBox .Show（ " done receving" ）;MessageBox.Show("done receving"); // byte [] stream = br.ReadBytes（size）;//byte[] stream = br.ReadBytes(size);   }  public void ProcessDownload（）public void ProcessDownload() { while （ true ）while (true) { string request = readLine（）;string request = readLine(); MessageBox .Show（request）;MessageBox.Show(request); StringBuilder response = new StringBuilder （）;StringBuilder response = new StringBuilder(); if （request.IndexOf（ " getFile＃" ）> = 0）if (request.IndexOf("getFile#") >= 0) { string [] tokens = request.Split （ '＃' ）;string[] tokens = request.Split('#'); string user =令牌[1];string user = tokens[1]; string filename = tokens [2];string filename = tokens[2]; 尝试try { FileInfo fi = new FileInfo （filename）;FileInfo fi = new FileInfo(filename); FileStream fileIn = fi.OpenRead（）;FileStream fileIn = fi.OpenRead(); BinaryReader br = new BinaryReader （fileIn）;BinaryReader br = new BinaryReader(fileIn); int filesize =（（ int ）fi.Length）;int filesize = ((int)fi.Length); response.Append（ " file＃" + filesize）;response.Append("file#" + filesize); sendLine（response.ToString（））;sendLine(response.ToString()); int bytes_read = 0，n = 0;int bytes_read = 0, n = 0; byte [] stream;byte[] stream; // FileStream fs = new FileStream（" test.pdf"，FileMode.Create）;// FileStream fs = new FileStream("test.pdf", FileMode.Create); dodo { if （filesize - bytes_read> MAX_BUFFER_SIZE）if (filesize - bytes_read > MAX_BUFFER_SIZE) stream = new byte [MAX_BUFFER_SIZE];stream = new byte[MAX_BUFFER_SIZE]; elseelse stream = new byte [filesize - bytes_read];stream = new byte[filesize - bytes_read]; //寻找未读取的下一个字节//seek the next byte not read fileIn.Seek（bytes_read， SeekOrigin .Begin）;fileIn.Seek(bytes_read, SeekOrigin.Begin); n = fileIn.Read（stream，0，stream.Length）;n = fileIn.Read(stream, 0, stream.Length); / * n = fileIn.read（stream，byte s_read，MAX_BUFFER_SIZE）; * //* n = fileIn.read(stream, bytes_read, MAX_BUFFER_SIZE);*/ bytes_read + = n;bytes_read += n; //发送字节//send bytes sendBytes（stream）;sendBytes(stream); / / fs.Write（stream，0，stream.Length）;// fs.Write(stream, 0, stream.Length); // fs.Close（）;//fs.Close(); // MessageBox.Show（" \tn ==" + n）;//MessageBox.Show("\tn ==" + n); Thread .Sleep（40）;Thread.Sleep(40);} 而 （（bytes_read< filesize ）&&（n！= -1））;while ((bytes_read < filesize) && (n != -1)); // fs.Close（）;//fs.Close(); MessageBox .Show（ " Done sending" ）;MessageBox.Show("Done sending");} catch （ 例外 e）catch (Exception e) { MessageBox .Show（e.Message）;MessageBox.Show(e.Message);} }} //}// } sendLine（ "Done \ n" ）;sendLine("Done\n");}}推荐答案 UDP不保证交付或包顺序。 这意味着要发送这样的文件，你需要在每个包含序列号的数据包上都有一个标题，并有一些确认系统来确认传递并在必要时重新发送部分文件。 通常情况下，当需要这些时，它表明您应该使用TCP而不是UDP。 -SteveUDP does not guarantee delivery or packet order.This means that to send a file like this, you need to have a header on every packet with a sequence number, and have some kind of acknowledgement system to confirm delivery and re-send parts of the file as necessary.Usually, when these are required, it's an indication that you should be using TCP instead of UDP.        -Steve 这篇关于UDP文件传输问题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ 上岸，阿里云！