我已为tcpip服务器编写（复制）代码。 我们有通过TCPIP发送消息的软件，并期望返回消息，表示接收已确认。这很好用。但在发送确认后，连接就会丢失。我不知道代码在哪里发生这种丢失。因此，当发送下一条消息时，没有连接，因此它会进行回滚并再次重新连接，然后发送消息。因此每次我发送多条消息时，我都会收到回滚警报。我们将不断整天发送消息。以下是代码：
class Program
{
// State object for reading client data asynchronously
public class StateObject
{
// Client socket.
public Socket workSocket = null;
// Size of receive buffer.
public const int BufferSize = 1024;
// Receive buffer.
public byte[] buffer = new byte[BufferSize];
// Received data string.
public StringBuilder sb = new StringBuilder();
}
public class AsynchronousSocketListener
{
// Thread signal.
public static ManualResetEvent allDone = new ManualResetEvent(false);
public AsynchronousSocketListener()
{
}
public static void StartListening()
{
// Data buffer for incoming data.
byte[] bytes = new Byte[1024];
// Establish the local endpoint for the socket.
// The DNS name of the computer
// running the listener is "host.contoso.com".
IPHostEntry ipHostInfo = Dns.Resolve(Dns.GetHostName());
IPAddress ipAddress = ipHostInfo.AddressList[0];
ipAddress = IPAddress.Parse("127.0.0.1");
IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 8080);
// Create a TCP/IP socket.
Socket listener = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
// Bind the socket to the local endpoint and listen for incoming connections.
try
{
listener.Bind(localEndPoint);
listener.Listen(100);
while (true)
{
// Set the event to nonsignaled state.
allDone.Reset();
// Start an asynchronous socket to listen for connections.
Console.WriteLine("Waiting for a connection...");
listener.BeginAccept(
new AsyncCallback(AcceptCallback),
listener);
// Wait until a connection is made before continuing.
allDone.WaitOne();
}
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
Console.WriteLine("\nPress ENTER to continue...");
Console.Read();
}
public static void AcceptCallback(IAsyncResult ar)
{
// Signal the main thread to continue.
allDone.Set();
ar.AsyncWaitHandle.WaitOne(100);
// Get the socket that handles the client request.
Socket listener = (Socket)ar.AsyncState;
Socket handler = listener.EndAccept(ar);
// Create the state object.
StateObject state = new StateObject();
state.workSocket = handler;
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
public static void ReadCallback(IAsyncResult ar)
{
String content = String.Empty;
String s1 = "MSH|^~\\&|BB|NSCCH|MILLENNIUM|BB|20150522080258137||ACK";
String s2 = "|20150522080258137883|P|2.4";//\r\nMSA|AA|Q245548634T287475114";
//String s3 = String.Empty;
String s4 = "MSA|AA|Q245548634T287475114";
//string s5 = "0x02";
int value = Convert.ToInt32("0x1C", 16);
char cc = (char)value;
int value_eob = Convert.ToInt32("0x0b", 16);
char eob = (char)value_eob;
int value_eod = Convert.ToInt32("0x0D", 16);
char eod = (char)value_eod;
int value_eoa = Convert.ToInt32("0x0A", 16);
char eoa = (char)value_eoa;
/*StringBuilder sb1 = new StringBuilder(s5);
sb1.Append(s1);
sb1.Append(s2);
s3 = sb1.ToString();*/
//byte[] s4 = Encoding.ASCII.GetBytes(s3);
// Retrieve the state object and the handler socket
// from the asynchronous state object.
StateObject state = (StateObject)ar.AsyncState;
Socket handler = state.workSocket;
// Read data from the client socket.
int bytesRead = handler.EndReceive(ar);
if (bytesRead > 0)
{
// There might be more data, so store the data received so far.
state.sb.Append(Encoding.ASCII.GetString(
state.buffer, 0, bytesRead));
// Check for end-of-file tag. If it is not there, read
// more data.
content = state.sb.ToString();
//s3 = state.sb.ToString();
// s3 = s1.ToString() + s2.ToString();
if (bytesRead < 1024) //content.IndexOf("<EOF>") > -1)
{
string s6 = eob.ToString() + s1 + s2 + eod.ToString() + s4 + cc.ToString() + eod.ToString() + eoa.ToString();// "\r\n";// +cc.ToString() + "\r\n";
// All the data has been read from the
// client. Display it on the console.
Console.WriteLine("Read {0} bytes from socket. \n Data : {1}",
content.Length, content);
Console.WriteLine("Send {0} bytes from socket. \n Data : {1}",
s6.Length, s6);
// Echo the data back to the client.
Send(handler, s6);
}
else
{
// Not all data received. Get more.
handler.BeginReceive(state.buffer, 0, StateObject.BufferSize, 0,
new AsyncCallback(ReadCallback), state);
}
}
else
{
if (content.Length > 0)
{
string s6 = eob.ToString() + s1 + s2 + eod.ToString() + s4 + cc.ToString() + eod.ToString() + eoa.ToString();// "\r\n";// +cc.ToString() + "\r\n";
// All the data has been read from the
// client. Display it on the console.
Console.WriteLine("Read {0} bytes from socket. \n Data : {1}",
content.Length, content);
Console.WriteLine("Send {0} bytes from socket. \n Data : {1}",
s6.Length, s6);
// Echo the data back to the client.
Send(handler, s6);
}
}
//添加了代码 handler.BeginReceive（state.buffer，0，StateObject.BufferSize，0， 新的AsyncCallback（ReadCallback），state）; }
private static void Send(Socket handler, String data)
{
// Convert the string data to byte data using ASCII encoding.
byte[] byteData = Encoding.ASCII.GetBytes(data);
// Begin sending the data to the remote device.
handler.BeginSend(byteData, 0, byteData.Length, 0,
new AsyncCallback(SendCallback), handler);
}
private static void SendCallback(IAsyncResult ar)
{
try
{
// Retrieve the socket from the state object.
Socket handler = (Socket)ar.AsyncState;
// Complete sending the data to the remote device.
int bytesSent = handler.EndSend(ar);
Console.WriteLine("Sent {0} bytes to client.", bytesSent);
// handler.Shutdown(SocketShutdown.Both);
// handler.Close();
}
catch (Exception e)
{
Console.WriteLine(e.ToString());
}
}
public static int Main(string[] args)
{
StartListening();
return 0;
}
}
}
答案 0 :(得分：2)
您的代码中至少有两个主要错误：
BeginReceive()。从那时起，这使得连接完全失效。另一个可能的错误是：
不幸的是，您的问题中没有提供足够的精确细节。短语＆＃34;连接退出＆＃34;是非特定的，没有明确的技术含义。这可能意味着您在套接字上出现错误，或者它可能只是意味着您从未收到任何更多数据，或者它可能完全意味着其他内容。
那就是说，如果你的意思是＆＃34;永远不会收到更多的数据＆＃34;，那么我会说上面的＃2错误很可能是你问题的根本原因。当然，＃1错误可以与＃2错误一起导致＆＃34;永远不会再收到任何数据＆＃34;。
没有a good, minimal, complete code example可靠地重现问题（请注意，对于与网络相关的问题，一个完整的示例包括连接的两个端点），无法确定所有的错误代码示例，不要介意实际问题是什么。但是，我建议修复上面的错误，看看是否有所改善。
作为一般规则，您的网络代码应如下运行：
Socket.Shutdown(SocketShutdown.Both)来实际关闭套接字。