《QT从基础到进阶·十六》QT实现客户端和服务端的简单交互

QT版本：5.15.2
VS版本：2019

客户端程序主要包含三块：连接服务器，发送消息，关闭客户端
服务端程序主要包含三块：打开消息监听，接收消息并反馈，关闭服务端

1、先打开服务端监听功能

void TCPServer::listen()
{initWsaData();//创建套接字sock = socket(AF_INET, SOCK_STREAM, 0);//创建地址簇对象sockaddr_in sin;sin.sin_family = AF_INET;sin.sin_port = htons(9888);sin.sin_addr.s_addr = htonl(INADDR_ANY);//绑定套接字int bindStatus = ::bind(sock, (struct sockaddr*)&sin, sizeof(sin));if (bindStatus == -1) {qDebug() << "socket bind failed!" << endl;ui.textBrowser->setText("socket bind failed!");return;}else {qDebug() << "socket bind success!" << endl;ui.textBrowser->setText("socket bind success!");}//将套接字设为监听模式，等待客户端连接int listenStatus = ::listen(sock, 128);if (listenStatus == -1) {qDebug() << "listen failed" << endl;ui.textBrowser->setText("listen failed");return;}else {qDebug() << "set listen success, server is listening..." << endl;ui.textBrowser->setText("set listen success, server is listening...");}//收到请求主后，接收连接请求，返回一个对应此次连接的新套接字//接受连接请求sockaddr_in sinAccept;int len = sizeof(sin);newSock = accept(sock, (struct sockaddr*)&sinAccept, &len);if (newSock == SOCKET_ERROR) {qDebug() << "connect failed" << endl;ui.textBrowser->setText("connect failed");return;}else {qDebug() << "connect success, ready to recv data" << endl;ui.textBrowser->setText("connect success, ready to recv data");}
}

2、点击客户端connect连接服务端

void TCPClient::Connect(const std::string ip, const int port)
{bool res = initWsaData(); //初始化套接字库if (!res) return;//常用协议族：AF_UNIX（本机通信）AF_INET（TCP/IP – IPv4）AF_INET6（TCP/IP – IPv6）//套接字类型：SOCK_STREAM（TCP流）SOCK_DGRAM（UDP数据报）SOCK_RAW（原始套接字）//protocol”一般设置为“0”sock = socket(AF_INET, SOCK_STREAM, 0);if (sock == SOCKET_ERROR) {qDebug() << "Failed to create socket" << endl;ui.textBrowser->setText("Failed to create socket");return;}else {qDebug() << "Socket created successfully" << endl;ui.textBrowser->setText("Socket created successfully");}//设置地址sockaddr_in sin;sin.sin_family = AF_INET;sin.sin_port = htons(port);sin.sin_addr.s_addr = inet_addr(ip.c_str());//连接服务器int connStatus = ::connect(sock, (struct sockaddr*)&sin, sizeof(sin));if (connStatus == -1) {qDebug() << "Failed to connect to the server" << endl;ui.textBrowser->setText("Failed to connect to the server");return;}
}

3、在客户端输入消息点击send发送到服务端

void TCPClient::DataTransmission()
{string msg = ui.lineEdit->text().toStdString();/*char sendBuf[MAX_MSG_SIZE];memset(sendBuf, 0, MAX_MSG_SIZE)*/;int sendStatus = send(sock, msg.c_str(), MAX_MSG_SIZE, 0);if (sendStatus == 0) {qDebug() << "Failed to send information" << endl;ui.textBrowser->setText("Failed to send information");//关闭套接字及套接字库closesocket(sock);WSACleanup();return;}char recvBuf[MAX_MSG_SIZE];memset(recvBuf, 0, MAX_MSG_SIZE);int recvStatus = recv(sock, recvBuf, MAX_MSG_SIZE, 0);if (recvStatus == -1) {qDebug() << "Failed to receive message" << endl;ui.textBrowser->setText("Failed to receive message");//关闭套接字及套接字库/* closesocket(sock);WSACleanup();*/return;}else {qDebug() << "Server information:" << recvBuf << endl;string msg = "---------Server information:" + string(recvBuf);ui.textBrowser->setText(QString::fromStdString(msg));}
}

4、在服务端点击send接收客户端消息并通知客户端已收到消息

void TCPServer::DataTransmission()
{//用新建立的套接字和客户端进行通信char recvBuf[MAX_MSG_SIZE];char sendBuf[MAX_MSG_SIZE];memset(recvBuf, 0, MAX_MSG_SIZE);memset(sendBuf, 0, MAX_MSG_SIZE);if (true) {int recvStatus = recv(newSock, recvBuf, MAX_MSG_SIZE, 0);if (recvStatus == -1) {qDebug() << "recv data failed" << endl;ui.textBrowser->setText("recv data failed");closesocket(sock);closesocket(newSock);WSACleanup();return;}else {qDebug() << "recv client new msg:" << recvBuf << endl;string msg = "--------------recv client new msg:" + string(recvBuf);ui.textBrowser->setText(QString::fromStdString(msg));}/*qDebug() << "请输入回复消息:";cin >> sendBuf;*/string sendMsg = "has recv msg-------";int sendStatus = send(newSock, sendMsg.c_str(), sizeof(sendBuf), 0);if (sendStatus == -1) {qDebug() << "msg send failed" << endl;ui.textBrowser->setText("msg send failed");closesocket(sock);closesocket(newSock);WSACleanup();return;}}
}