我做了个TCP服务器程序,用来监听各个客户端的连接,并与之通信。照着书上用异步的方式写了程序,以下是代码。
private void AcceptConnect()
{
IPAddress[] ip = Dns.GetHostAddresses(Dns.GetHostName());
listener = new TcpListener(ip[0], 51888);
listener.Start();
listBoxStatus.Invoke(setListBoxCallback, "开始等待客户连接");
while (isExit == false)
{
try
{
allDone.Reset();
AsyncCallback callback = new AsyncCallback(AcceptTcpClientCallback);
listener.BeginAcceptTcpClient(callback,listener);
allDone.WaitOne();
}
catch (Exception ex)
{
listBoxStatus.Invoke(setListBoxCallback,ex.Message);
break;
}
}
} private void AcceptTcpClientCallback(IAsyncResult ar)
{
try
{
allDone.Set();
TcpListener myListener = (TcpListener)ar.AsyncState;
TcpClient client = myListener.EndAcceptTcpClient(ar);
listBoxStatus.Invoke(setListBoxCallback, "已接受客户连接:" + client.Client.RemoteEndPoint);
comboBox1.Invoke(setComboBoxCallback,client.Client.RemoteEndPoint.ToString());
ReadWriteObject readWriteObject = new ReadWriteObject(client);
clientList.Add(readWriteObject);
SendString(readWriteObject,"服务器已经接受连接");
readWriteObject.netStream.BeginRead(readWriteObject.readBytes,0,readWriteObject.readBytes.Length,ReadCallback,readWriteObject);
}
catch(Exception ex)
{
listBoxStatus.Invoke(setListBoxCallback, ex.Message);
}
}
private void ReadCallback(IAsyncResult ar)
{
try
{
ReadWriteObject readWriteObject = (ReadWriteObject)ar.AsyncState;
int count = readWriteObject.netStream.EndRead(ar);
richTextBoxReceive.Invoke(setRichTextBoxCallback,string.Format("[来自{0}]{1}",readWriteObject.client.Client.RemoteEndPoint,str));
if(isExit==false)
{
readWriteObject.InitReadArray();
readWriteObject.netStream.BeginRead(readWriteObject.readBytes, 0, readWriteObject.readBytes.Length, ReadCallback, readWriteObject);
}
}
catch(Exception ex)
{
//listBoxStatus.Invoke(setListBoxCallback,ex.Message);
}
}
基本按这个代码来的,小有改动。运行结果达到预期,但是发现两个问题,一个是CPU占用率会一直上升到100%,二是内存一直在涨。
第一个问题,我加了Thread.Sleep(1)解决问题。第二个问题我认为是出在AcceptConnection里,因为客户端会每隔1分钟都给我发个连接,我的服务器程序没有判断功能,对重复的连接也进行操作了,致使在没有新客户的情况下也新开线程。事实也是如此,通过任务管理器也可以看出我这个程序的线程数一直在增加。我在AcceptTcpClientCallback里做了个判断,对于重复的IP和端口直接返回,但是我不知道AcceptConnection里的callback如何释放掉。不知我的理解对否,求解答。
private void AcceptConnect()
{
IPAddress[] ip = Dns.GetHostAddresses(Dns.GetHostName());
listener = new TcpListener(ip[0], 51888);
listener.Start();
listBoxStatus.Invoke(setListBoxCallback, "开始等待客户连接");
while (isExit == false)
{
try
{
allDone.Reset();
AsyncCallback callback = new AsyncCallback(AcceptTcpClientCallback);
listener.BeginAcceptTcpClient(callback,listener);
allDone.WaitOne();
}
catch (Exception ex)
{
listBoxStatus.Invoke(setListBoxCallback,ex.Message);
break;
}
}
} private void AcceptTcpClientCallback(IAsyncResult ar)
{
try
{
allDone.Set();
TcpListener myListener = (TcpListener)ar.AsyncState;
TcpClient client = myListener.EndAcceptTcpClient(ar);
listBoxStatus.Invoke(setListBoxCallback, "已接受客户连接:" + client.Client.RemoteEndPoint);
comboBox1.Invoke(setComboBoxCallback,client.Client.RemoteEndPoint.ToString());
ReadWriteObject readWriteObject = new ReadWriteObject(client);
clientList.Add(readWriteObject);
SendString(readWriteObject,"服务器已经接受连接");
readWriteObject.netStream.BeginRead(readWriteObject.readBytes,0,readWriteObject.readBytes.Length,ReadCallback,readWriteObject);
}
catch(Exception ex)
{
listBoxStatus.Invoke(setListBoxCallback, ex.Message);
}
}
private void ReadCallback(IAsyncResult ar)
{
try
{
ReadWriteObject readWriteObject = (ReadWriteObject)ar.AsyncState;
int count = readWriteObject.netStream.EndRead(ar);
richTextBoxReceive.Invoke(setRichTextBoxCallback,string.Format("[来自{0}]{1}",readWriteObject.client.Client.RemoteEndPoint,str));
if(isExit==false)
{
readWriteObject.InitReadArray();
readWriteObject.netStream.BeginRead(readWriteObject.readBytes, 0, readWriteObject.readBytes.Length, ReadCallback, readWriteObject);
}
}
catch(Exception ex)
{
//listBoxStatus.Invoke(setListBoxCallback,ex.Message);
}
}
基本按这个代码来的,小有改动。运行结果达到预期,但是发现两个问题,一个是CPU占用率会一直上升到100%,二是内存一直在涨。
第一个问题,我加了Thread.Sleep(1)解决问题。第二个问题我认为是出在AcceptConnection里,因为客户端会每隔1分钟都给我发个连接,我的服务器程序没有判断功能,对重复的连接也进行操作了,致使在没有新客户的情况下也新开线程。事实也是如此,通过任务管理器也可以看出我这个程序的线程数一直在增加。我在AcceptTcpClientCallback里做了个判断,对于重复的IP和端口直接返回,但是我不知道AcceptConnection里的callback如何释放掉。不知我的理解对否,求解答。
客户发起了连接,如果没有及时socket.Disconnect或tcpClient.Close,那么服务方就要空等着。在服务端ReadCallback方面,没有断线后清理连接资源的措施。加上你把资源放到clientList里面,将导致内存不能回收。
AcceptConnect()是在一个新建的线程里。
如果是重复的连接我在“ReadWriteObject readWriteObject = new ReadWriteObject(client);”之前就return了。而且断线后,我会把clientList里的相应项删除,应该不会造成资源释放不了。而且断线后,读数据有异常,会退出循环,结束ReadCallback。我就是不知道new的callback怎么释放掉。
{
IPAddress[] ip = Dns.GetHostAddresses(Dns.GetHostName());
listener = new TcpListener(ip[0], 51888);
listener.Start();
listBoxStatus.Invoke(setListBoxCallback, "开始等待客户连接");
AcceptTcpClientCallback();
listener.BeginAcceptTcpClient(AcceptTcpClientCallback,listener);
} private void AcceptTcpClientCallback(IAsyncResult ar)
{
try
{
TcpListener myListener = (TcpListener)ar.AsyncState;
TcpClient client = myListener.EndAcceptTcpClient(ar);
listBoxStatus.Invoke(setListBoxCallback, "已接受客户连接:" + client.Client.RemoteEndPoint);
comboBox1.Invoke(setComboBoxCallback,client.Client.RemoteEndPoint.ToString());
ReadWriteObject readWriteObject = new ReadWriteObject(client);
clientList.Add(readWriteObject);
SendString(readWriteObject,"服务器已经接受连接");
readWriteObject.netStream.BeginRead(readWriteObject.readBytes,0,readWriteObject.readBytes.Length,ReadCallback,readWriteObject);
}
catch(Exception ex)
{
listBoxStatus.Invoke(setListBoxCallback, ex.Message);
}
listener.BeginAcceptTcpClient(AcceptTcpClientCallback,listener);
}本来是赶紧整洁的代码,就好像漂亮的姑娘,带上一个while式的垃圾帽子就显得臃肿和俗气了。你的ReadCallback也是类似,如果需要连续读取数据,那么在这个方法内部应该调用BeginRead,而不是在 AcceptTcpClientCallback 内部搞什么 while 语句和阻塞。
我试用你的方式改写了程序,还不错,我感觉比用allDone好理解一些。另:
我发现了当初CPU占用率一直增长的原因,是出在ReadCallback里,是它一直在反复自调用。我追踪了下,除了正常接收数据外,程序还在无休止地接收长度为0的报文。如果说是客户端设计地不好,可是我用WireShark分析时,并没有检测到这些长度为0的报文啊,求解。
不是吧。我无视,可是程序处理它啊。我目前只有在ReadCallback里加上Thread.Sleep(),才能把CPU占用率降下来。
今天发现了这句。如果当前使用的是面向连接的 Socket,那么 Receive 方法将会读取所有可用的数据,直到达到缓冲区的大小为止。如果远程主机使用 Shutdown 方法关闭了 Socket 连接,并且所有可用数据均已收到,则 Receive 方法将立即完成并返回零字节。
http://msdn.microsoft.com/zh-cn/library/8s4y8aff(v=vs.80).aspx