一、异步读写
在 Qt 中实现 TCP 客户端和服务器的同步和异步读写消息涉及使用 QTcpSocket 和 QTcpServer 类。这两个类提供了用于建立 TCP 连接、发送和接收数据的功能。下面是一个简单的示例，演示了如何在 Qt 中实现 TCP 客户端和服务器的同步和异步读写消息：
TCP 服务器端示例（异步）
#include <QCoreApplication>
#include <QTcpServer>
#include <QTcpSocket>
#include <QDebug>
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QTcpServer server;
server.listen(QHostAddress::Any, 1234); // 监听端口 1234
QObject::connect(&server, &QTcpServer::newConnection, [&](){
QTcpSocket* clientSocket = server.nextPendingConnection();
QObject::connect(clientSocket, &QTcpSocket::readyRead, [&](){
QByteArray requestData = clientSocket->readAll();
qDebug() << "Received request from client:" << requestData;
// Echo back the received data
clientSocket->write(requestData);
});
});
qDebug() << "TCP server started. Listening on port 1234...";
return a.exec();
}
TCP 客户端端示例（异步）
#include <QCoreApplication>
#include <QTcpSocket>
#include <QDebug>
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QTcpSocket client;
client.connectToHost("127.0.0.1", 1234); // 连接到服务器的 IP 地址和端口
QObject::connect(&client, &QTcpSocket::connected, [&](){
qDebug() << "Connected to server.";
// Send a message to the server
client.write("Hello, Server!");
});
QObject::connect(&client, &QTcpSocket::readyRead, [&](){
QByteArray responseData = client.readAll();
qDebug() << "Received response from server:" << responseData;
});
return a.exec();
}
示例简单演示了如何在 Qt 中实现 TCP 客户端和服务器的异步读写消息。在异步通信中，使用信号和槽机制来处理数据的接收和发送。
二、同步读写
以下是一个简单的示例，演示了如何在 Qt 中实现 TCP 客户端和服务器的同步读写消息：
TCP 服务器端示例（同步）
#include <QCoreApplication>
#include <QTcpServer>
#include <QTcpSocket>
#include <QDebug>
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QTcpServer server;
server.listen(QHostAddress::Any, 1234); // 监听端口 1234
if (!server.isListening()) {
qDebug() << "Failed to start TCP server.";
return 1;
}
QTcpSocket* clientSocket = nullptr;
while (true) {
if (server.hasPendingConnections()) {
clientSocket = server.nextPendingConnection();
break;
}
}
if (clientSocket) {
qDebug() << "Client connected.";
// Read data from client
QByteArray requestData = clientSocket->readAll();
qDebug() << "Received request from client:" << requestData;
// Echo back the received data
clientSocket->write(requestData);
}
return a.exec();
}
TCP 客户端端示例（同步）
#include <QCoreApplication>
#include <QTcpSocket>
#include <QDebug>
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
QTcpSocket client;
client.connectToHost("127.0.0.1", 1234); // 连接到服务器的 IP 地址和端口
if (!client.waitForConnected()) {
qDebug() << "Failed to connect to server.";
return 1;
}
qDebug() << "Connected to server.";
// Send a message to the server
client.write("Hello, Server!");
if (!client.waitForBytesWritten()) {
qDebug() << "Failed to write data to server.";
return 1;
}
if (!client.waitForReadyRead()) {
qDebug() << "Failed to read response from server.";
return 1;
}
// Read response from server
QByteArray responseData = client.readAll();
qDebug() << "Received response from server:" << responseData;
return a.exec();
}
示例简单演示了如何在 Qt 中实现 TCP 客户端和服务器的同步读写消息。在同步通信中，使用 waitForConnected、waitForBytesWritten 和 waitForReadyRead 等方法来等待连接建立、数据写入和数据读取完成。这种方式适用于需要确保数据传输完整性和顺序性的场景。
