TCP协议通信

**特点：**优点不丢包，可以传输内容大的数据，
**缺点：**传输效率慢于UDP，
**使用场合：**适合进程间文件，图片，视频发送。
**原理：**3次握手，第一次客户端发送连接请求，服务端确认AK置1，第二次服务端返回确认连接请求，客户端接收AK置1，第三次客户端NAK置1，发送连接成功，服务端NAK置1，确认连接成功。

客户端：
初始化绑定IP和端口号
QTcpSocket tcpSocket = new QTcpSocket(this);
Int port = 5555;
tcpSocket.connectToHost(“127.0.0.1”,port);
发送数据，
QByteArray sendData;
tcpSocket.write(sendData,sendData.length);
接收数据

服务端：
初始化某些地址和端口号监听连接；
QTcpServer tcpServer = new QTcpServer(this);
Int port = 5555;
tcpServer.listen(QHostAddress::Any,port);
connect(tcpServer,&QTcpServer::newConnection;this,&Dialog::incomming);
连接成功建立通信；
QTcpSocket tcpSocket = tcpServer.nextPending();
QList> tcpSocketList;
tcpSocketList.append(tcpSocket);
connect(tcpSocket,&QAbstractSocket::connected,this,&Dialog::onConnected);
connect(tcpSocket,&QAbstractSocket::disconnected,this,&Dialog::onDisconnected);
void (QAbstractSocket *send)(QAbstractSocket::SocketError socketError) = &QAbstractSocket:error;
Void (Dialog *rev)(QAbstractSocket::SocketError socketError) = &Dialog::onError;
connect(tcpSocket,send,this,rev);
connect(tcpSocket,&QIODevice::readyRead,this,&Dialog::readData);
接收数据
QObject *obj = this.sender();
QTcpSocket *socket = qobject_cast(obj);
While(socket.bytesAvailiable())
{
Int size = socket.bytesAvailiable();
QByteArray revData;
revData.resize(size);
Socket.read(revData.data(),revData.size());
QString msg = QString::fromLocat8Bit(revData,revData,size());
}
发送数据