我想使用 StreamReader 和 StreamWriter 通过 TCPClient.NetworkStream 接收和发送数据。代码如下所示:
客户端代码:
using (TcpClient client = new TcpClient())
{
IPEndPoint localEndPoint = new IPEndPoint(IPAddress.Parse("127.0.0.1"), 9001);
client.Connect(localEndPoint);
client.NoDelay = true;
using(NetworkStream stream = client.GetStream())
{
using (StreamWriter writer = new StreamWriter(stream))
{
writer.AutoFlush = true;
using (StreamReader reader = new StreamReader(stream))
{
string message = "Client says: Hello";
writer.WriteLine(message);
// If I comment the line below, the server receives the first message
// otherwise it keeps waiting for data
string response = reader.ReadToEnd();
Console.WriteLine(response);
}
;
}
}
}
注意:如果我评论 reader.ReadToEnd();然后服务器接收消息,否则服务器一直等待来自客户端的数据。 ReadToEnd 是问题所在吗?
服务器代码异步接受连接,但以同步方式处理数据:
class Program
{
private static AsyncCallback tcpClientCallback;
static void Main(string[] args){
IPEndPoint localEndPoint = new IPEndPoint(IPAddress.Parse("127.0.0.1"),9001);
TcpListener listener = new TcpListener(localEndPoint);
listener.Start();
tcpClientCallback = new AsyncCallback(ConnectCallback);
AcceptConnectionsAysnc(listener);
Console.WriteLine("Started Aysnc TCP listener, press any key to exit (server is free to do other tasks)");
Console.ReadLine();
}
private static void AcceptConnectionsAysnc(TcpListener listener)
{
listener.BeginAcceptTcpClient(tcpClientCallback, listener);
}
static void ConnectCallback(IAsyncResult result)
{
Console.WriteLine("Received a conenct request");
TcpListener listener = (TcpListener)result.AsyncState;
// We are starting a thread which waits to receive the data
// This is not exactly scalable
Task recieveTask = new Task(() => { HandleRecieve(result, listener); });
recieveTask.Start();
AcceptConnectionsAysnc(listener);
}
// This makes a blocking call - that means until the client is ready to
// send some data the server waits
private static void HandleRecieve(IAsyncResult result, TcpListener listener)
{
Console.WriteLine("Waiting for data");
using (TcpClient client = listener.EndAcceptTcpClient(result))
{
client.NoDelay = true;
using (NetworkStream stream = client.GetStream())
{
using (StreamReader reader = new StreamReader(stream))
{
using (StreamWriter writer = new StreamWriter(stream))
{
writer.AutoFlush = true;
Stopwatch watch = new Stopwatch();
watch.Start();
string data = reader.ReadToEnd();
watch.Stop();
Console.WriteLine("Time: " + watch.Elapsed.TotalSeconds);
Console.WriteLine(data);
// Send a response to client
writer.WriteLine("Response: " + data);
}
}
}
}
}
}
最佳答案
流在关闭之前不会结束。目前,客户端和服务器都保持连接打开,并且都试图从对方读取到最后 - 当它们这样做时,将关闭自己。这是一个僵局:两者都不会到达终点,因此也永远不会关闭(这将允许另一个到达终点)。
选项:
使用原始套接字,并让客户端在发送后关闭出站流:
socket.Shutdown(SocketShutdown.Send);
这让服务器读取完成,这让服务器关闭,让客户端读取完成;关闭出站套接字后,客户端仍然可以从入站流中读取数据。
使用与
ReadToEnd
不同的终止隐喻;对于基于文本的协议(protocol),行尾是最常见的(因此:ReadLine
);对于二进制协议(protocol),消息的长度前缀是最常见的。这允许每一端读取下一条消息,而不必读取到流的末尾。在这种情况下,它只会一条消息,但该策略仍然有效。- 如果您发现上述问题很棘手,请使用不同的协议(protocol); http 适用于单个请求/响应操作,并且可以通过
HttpListener
在服务器上进行处理。
此外,我会非常小心地在服务器上使用 ReadToEnd
(甚至是 ReadLine
)——这可能是在服务器上锁定线程的好方法.如果服务器需要处理高吞吐量和大量连接,则首选基于原始套接字的异步 IO。
关于c# - TCPClient收不到数据,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/13134458/