通过TCP发送长XML

本文关键字:XML TCP 通过 | 更新日期: 2023-09-27 18:12:25

我正在发送一个对象(类名House)通过TCP使用TcpListener在服务器端响应从TcpClient收到的任何消息。

消息收到时,当前正在填充名为textBox1的文本框。

如果我发送一行文本,它可以正常工作。您会注意到我有一个多余的行"Hello,我是一个服务器"来测试这个目的。但是当我发送XML时,它会过早地将其截断。

当我将序列化XML发送到流中时,我也从服务器端接收到这个错误:

无法从传输连接读取数据:已存在连接被远程主机强制关闭。

这是我的服务器代码

// Set the variables for the TCP listener
Int32 port = 14000;
IPAddress ipaddress = IPAddress.Parse("132.147.160.198");
TcpListener houseServer = null;
// Create IPEndpoint for connection
IPEndPoint ipend = new IPEndPoint(ipaddress, port);
// Set the server parameters
houseServer = new TcpListener(port);
// Start listening for clients connecting
houseServer.Start();
// Buffer for reading the data received from the client
Byte[] bytes = new Byte[256];
String data = "hello, this is a house";
// Show that the TCP Listener has been initialised
Console.WriteLine("We have a TCP Listener, waiting for a connection...");
// Continuing loop looking for 
while (true)
{
    // Create a house to send
    House houseToSendToClient = new House
    {
        house_id = 1,
        house_number = 13,
        street = "Barton Grange",
        house_town = "Lancaster",
        postcode = "LA1 2BP"
    };
    // Get the object serialised
    var xmlSerializer = new XmlSerializer(typeof(House));
    using (var memoryStream = new MemoryStream())
    {
        xmlSerializer.Serialize(memoryStream, houseToSendToClient);
    }
    // Accept an incoming request from the client
    TcpClient client = houseServer.AcceptTcpClient();
    // Show that there is a client connected
    //Console.WriteLine("Client connected!");
    // Get the message that was sent by the server
    NetworkStream stream = client.GetStream();
    // Blank int
    int i;
    // Loop for receiving the connection from the client
    // >>> ERROR IS ON THIS LINE <<<
    while ((i = stream.Read(bytes, 0, bytes.Length)) != 0)
    {
        Console.WriteLine("here");
        // Take bytes and convert to ASCII string
        data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);
                Console.WriteLine("Received s, return house");
                // Convert the string to a byte array, ready for sending
                Byte[] dataToSend = System.Text.Encoding.ASCII.GetBytes("Hello, I'm a server");
                // Send the data back to the client
                //stream.Write(dataToSend, 0, dataToSend.Length);
                // Send serialised XML in to the stream
                xmlSerializer.Serialize(stream, houseToSendToClient);
    }
    // Close the connection
    client.Close();
}
客户机代码

// Get the object serialised
var xmlSerializer = new XmlSerializer(typeof(House));
// Set the variables for the TCP client
Int32 port = 14000;
IPAddress ipaddress = IPAddress.Parse("127.0.0.1");
IPEndPoint ipend = new IPEndPoint(ipaddress, port);
string message = "s";
try
{
    // Create TCPCLient
    //TcpClient client = new TcpClient("localhost", port);
    TcpClient client = new TcpClient();
    // Convert the string to a byte array, ready for sending
    Byte[] dataToSend = System.Text.Encoding.ASCII.GetBytes(message);
    // Connect using TcpClient
    client.Connect(ipaddress, port);
    // Client stream for reading and writing to server
    NetworkStream stream = client.GetStream();
            // Send the data to the TCP Server
            stream.Write(dataToSend, 0, dataToSend.Length);
            //xmlSerializer.Serialize(stream, houseToSend);                        
            // Buffer to store response
            Byte[] responseBytes = new Byte[256];
            string responseData = String.Empty;
            // Read the response back from the server
            Int32 bytes = stream.Read(responseBytes, 0, responseBytes.Length);
            responseData = System.Text.Encoding.ASCII.GetString(responseBytes, 0, bytes);
            textBox1.Text = responseData;

        // Close the stream and the client connection
        stream.Close();
        client.Close();
}
catch (SocketException e)
{
    MessageBox.Show(e.ToString());
}
catch (Exception e)
{
    MessageBox.Show(e.ToString());
}

我已经在代码中标出了出现错误的地方。

是因为消息太长吗?

通过TCP发送长XML

您的客户端代码假设整个消息将通过对Read(...)方法的一次调用完成,这是绝对错误的。来自MSDN文档:"一个实现可以自由地返回比请求更少的字节,即使流的末端还没有到达。"

对于1024字节的XML文档,可能需要调用Read(...) 1024次才能获得整个消息。

实际上,最好在发送XML之前发送一个4字节的长度,这样客户端就知道需要发送多少数据。客户端将读取四个字节,将其转换为整数长度,然后读取更多的字节,然后将这些字节转换为XML。