java - 为什么通过套接字传输数据后，文件中的数据丢失了？

Question

当尝试将文件上传到服务器或从服务器下载文件时，我为服务器和客户端编写了相同的代码。

从服务器下载工作正常，我的文件中没有丢失任何数据，但由于某种原因，上传文件时，并未传输所有数据。

例如，我客户端上的文件大小比服务器上的文件大小小。然后，当它在服务器上打开时，并非全部都在那里(因为并非全部都已收到)

服务器:

算法:

• 从客户端获取消息
• 客户端告诉服务器它想要发送文件(推送)

服务器读取文件存放位置，然后从客户端接收文件

  public static void GetClientMessage() {

            while (true) {
                try {

                    try {

                        try {
                            serverSocket = new ServerSocket(PORT_NUMBER);
                        } catch (IOException ex) {
                            System.out.println("GetClientMessage():serverSocket:IOException:ex " + ex);
                            SendBackException(ex.toString());  // Inform client
                        }
                        try {
                            System.out.println("Waiting for client");
                            socket = serverSocket.accept();
                        } catch (IOException ex) {
                            System.out.println("GetClientMessage():socket = serverSocket.accept():IOException:ex " + ex);
                            SendBackException(ex.toString());  // Inform client
                        }

                        bufOut = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
                        brffReadIn = new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF-8"));

                        // 1 - Read Line (it is the flag)
                        flag = brffReadIn.readLine();
                        // 2 - Handle Flag
                        HandleClientMessage(flag);

                        // Make decisions based upon that message
                    } catch (IOException ex) {
                        System.out.println("GetClientMessage():IOException:ex: " + ex);
                        SendBackException(ex.toString());  // Inform client
                    }

                    socket.close();
                    serverSocket.close();

                } // Close while loop
                catch (IOException ex) {
                    System.out.println("GetClientMessage:serverSocket.close():IOException:ex " + ex);
                }

            }

        }

           public static void HandleClientMessage(String message) {
           System.out.println("HandleClientMessage:message: '" + message + "'");
            switch (message) {
                case "push":
                    GetClientFile();
                    break;
                case "open_cla":
                    OpenCla();
                    break;
                case "kill_cla":
                    KillCla();
                    break;
                case "get":                
                    SendFile();
                    break;
                default:
                    break;
            }
        }

        // Gets path to where to place file on local
        public static String GetPath() {

            String filePath = " ";

            try {

                bufOut = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
                brffReadIn = new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF-8"));

                filePath = brffReadIn.readLine();

                System.out.println("Path to place file on local: " + filePath);

            } catch (IOException ex) {
                System.out.println(("GetPath():IOException:ex: " + ex));
            }
            return filePath;
        }

        public static void GetClientFile() {

            // Get the location where to place the file on local
            fileOnLocal = GetPath();

            int count;
            try {

                File file = new File(fileOnLocal);
                // Get the size of the file
                long length = file.length();
                byte[] bytes = new byte[16* 1024];
                InputStream in = socket.getInputStream();
                OutputStream out = new FileOutputStream(fileOnLocal);

                while ((count = in.read(bytes)) > 0) {
                    System.out.println("strByteArray: " + strByteArray);
                    out.write(bytes, 0, count);
                }
                out.flush();

                System.out.println("File Size in bytes: " + file.length());
                if (file.length() < 5) {
                    System.out.println("FileClient:Error:File:" + fileOnLocal + " not found on server");
                    out.close();
                    in.close();
                    socket.close();
                    file.delete();
                    System.out.println("File:" + file.getAbsolutePath() + " deleted");
                } else {
                    out.close();
                    in.close();
                    socket.close();
                }

            } catch (IOException ex) {
                System.out.println(":FileClient:GetServerFile():IOException:ex:" + ex);
            }
        }

客户端代码:

客户端告诉服务器它想要“推送”文件，然后传递文件在服务器上的位置，然后传输文件

public void SendFlagToServer(String flag){

        try {

            bufOut = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
            brffReadIn = new BufferedReader(new InputStreamReader(socket.getInputStream(), "UTF-8"));

            bufOut.write(flag);
            bufOut.newLine();
            bufOut.flush();

            System.out.println(host + ":SendFlagToServer: " + flag);

        } catch (IOException ex) {
            Logger.Log((host + ":FileClient:SendFileToGetToServer():IOException:ex: " + ex));
        }
    }

执行此操作后，客户端会收到字节，但不是全部字节。我编码有错误吗？我的 byte[] 数组应该有不同的大小吗？这将在 Win7 和 Win8 上使用，将来可能还会在 Mac 上使用。

编辑:我明白了。我试图太快地发送一条消息，然后发送一串字节。

这解决了我的问题:

SendFlagToServer(fileLocaitonOnServer);
Thread.sleep(1000);
....

Answer 1

您将在第一个客户端连接后关闭套接字

socket.close();
serverSocket.close();

解决方案:

• Once you accept a client socket, create a new Thread with the socket connection and handle all IO operations in that thread

• Do not close serverSocket. Once you close serverSocket, no more client socket connections will be accepted.

您能提供您遇到的异常(exception)情况吗？