套接字编程，编码/解码数据/文本，通过套接字发送和接收更具体的特殊字符

Question

Win 10 64位C服务器：

const int BufLen = 1024;
char RecvBuf[BufLen];
int result;
char SendBuf[BufLen] ;

const int PORT = 27015;
const char* HOST = "127.0.0.1";

int main()
{
    //SetConsoleOutputCP(65001);
    std::cout << "Hello World!\n";
    //std::cout << "á" << std::endl;
    WSADATA wsaData; 
    int iResult = WSAStartup(MAKEWORD(2, 2), &wsaData);   if (iResult != NO_ERROR) {
        printf("Error at WSAStartup()\n");     
        return 1;
    }
    // Create a SOCKET for listening for   // incoming connection requests. 
    SOCKET ListenSocket;
    ListenSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);

    if (ListenSocket == INVALID_SOCKET) {
        printf("Error at socket(): %ld\n", WSAGetLastError());    
        WSACleanup();  
        return 1;
    
    }
    // The sockaddr_in structure specifies the address family,
    // IP address, and port for the socket that is being bound.

    sockaddr_in service;

    service.sin_family = AF_INET;
    //service.sin_addr.s_addr = inet_addr("127.0.0.1");
    inet_pton(AF_INET, HOST, &service.sin_addr);
    service.sin_port = htons(PORT);

    if (bind(ListenSocket, (SOCKADDR*)&service, sizeof(service)) == SOCKET_ERROR) { 
        printf("bind() failed.\n"); 
        closesocket(ListenSocket); 
        WSACleanup(); 
        return 1;
    }
    // Listen for incoming connection requests.
    // on the created socket
    if (listen(ListenSocket, 1) == SOCKET_ERROR) { 
        printf("Error listening on socket.\n");
        closesocket(ListenSocket); WSACleanup();
        return 1; 
    }

    // Create a SOCKET for accepting incoming requests. SOCKET AcceptSocket; printf("Waiting for client to connect...\n");
    SOCKET AcceptSocket;
    printf("Waiting for client to connect...\n");

    // Accept the connection.
    AcceptSocket = accept( ListenSocket, NULL, NULL );
    if (AcceptSocket == INVALID_SOCKET) {
        printf("accept failed: %d\n", WSAGetLastError()); 
        closesocket(ListenSocket);
        WSACleanup(); 
        return 1;
    }
    else printf("Client connected.\n");
    // Call the recvfrom function to receive datagrams 
    // on the bound socket.
    
    printf("Receiving datagrams...\n");
    result = recv(AcceptSocket, RecvBuf, BufLen, 0);
   
    printf("%d\n", result);
    std::cout << "Received:" << RecvBuf << std::endl;
    printf("%d", sizeof(RecvBuf));
    //strcpy_s(SendBuf, "Helloéáőúóü");
    printf("\n\n\n\n");
    strcpy_s(SendBuf, "abcá");
    std::cout << SendBuf << std::endl;
    result = send(AcceptSocket, SendBuf, BufLen, 0);
    printf("\nAfter sending: %d\n", result);
    std::cout << SendBuf;

Java客户端：

 var socket = new Socket("127.0.0.1", 27015);
        //sending to the server
        var out = new PrintWriter(socket.getOutputStream(), true);
        out.println("Helloá");
        //receive from server
        var in = new InputStreamReader(socket.getInputStream());
        BufferedReader br = new BufferedReader(in);
        char[] buffer = new char[1024];
        int count = br.read(buffer, 0, 20);
        String reply = new String(buffer, 0, count);
        System.out.println(reply);

Python客户端：

HOST = "127.0.0.1"
PORT =  27015
clientSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
clientSocket.connect((HOST, PORT))
clientSocket.send("JAASFSKF".encode('utf-8'))
msg = clientSocket.recv(1024)
print(msg)
msg = msg.decode('utf-8')
print(msg)
clientSocket.close()

运行了一些特殊字符的实验，但客户端或服务器都无法处理它。

java客户端结果：使用utf-8完成编码，python应用程序抛出异常，因为它无法解码从socket:Python3.9接收的数据。5我试图用不同的编码保存服务器，但我认为情况并非如此，可能需要对套接字声明进行一些更改。客户端与服务器是同一台机器。这是我的实际问题，要克服这个问题

Answer 1

TCP套接字携带字节流而不进行解释。没有“特殊字符”。

你的C代码显然是在处理字节；Python和Java代码希望这些字节表示编码为UTF-8的“字符”。这是一种设计不匹配。

如果您的目的是通信使用UTF-8，则C代码应显式转换为UTF-8或从UTF-8转换。

此外，TCP中没有“消息”。这是一个字节streaam协议。您需要一个约定，以便每个终端可以确定它是否收到了应用程序希望作为消息的内容。

如果一方发送“xyz”（并且没有立即关闭连接），另一方如何知道“z”是最终字符？

由于您使用的是字符，一种方法是确保所有字符都以换行符“\n”结尾。您可以使用面向行的方法。