Qt 网络进阶｜TCP 通信 + 粘包彻底解决 + WebSocket 实时通信-开发者社区

一、模块引入

pro

QT += network

cmake

find_package(Qt6 REQUIRED COMPONENTS Network) target_link_libraries(App PRIVATE Qt6::Network)

第一部分：TCP 通信 + 粘包问题解决

1. TCP 基础说明

TCP 是面向字节流协议，无数据包边界；
发送端多次小数据，内核会合并发送 →粘包；
接收端一次读取可能包含多条数据。

粘包本质：数据之间没有边界，接收方无法区分一条完整消息。

2. 通用解决方案（工业常用 2 种）

包头 + 包体：固定 4 字节表示数据长度，先读长度，再读对应字节数（推荐）
特殊分隔符：末尾加\r\n、###等标记（文本协议适用）

下文使用「长度头」方案实现完整 TCP 客户端 / 服务端，并彻底解决粘包。

3. TCP 服务端（QTcpServer + QTcpSocket）

cpp

运行

#include <QApplication> #include <QMainWindow> #include <QTcpServer> #include <QTcpSocket> #include <QVBoxLayout> #include <QTextEdit> #include <QByteArray> class TcpServer : public QMainWindow { Q_OBJECT public: TcpServer() { resize(500,300); m_server = new QTcpServer(this); m_recvEdit = new QTextEdit; setCentralWidget(m_recvEdit); // 监听本机 8888 端口 if(m_server->listen(QHostAddress::Any, 8888)) m_recvEdit->append("服务端启动成功，端口:8888"); else m_recvEdit->append("服务端启动失败"); connect(m_server, &QTcpServer::newConnection, this, &TcpServer::onNewConn); } private slots: void onNewConn() { m_socket = m_server->nextPendingConnection(); m_recvEdit->append("客户端已连接"); connect(m_socket, &QTcpSocket::readyRead, this, &TcpServer::onReadData); connect(m_socket, &QTcpSocket::disconnected, m_socket, &QTcpSocket::deleteLater); } // 核心：拆包、解决粘包 void onReadData() { m_buffer += m_socket->readAll(); // 至少4字节(长度头) + 一条数据 while(m_buffer.size() >= 4) { // 读取前4字节 = 数据长度 quint32 len = *(quint32*)m_buffer.data(); if(m_buffer.size() < 4 + len) break; // 数据不完整，等待下一次接收 // 截取完整数据包 QByteArray data = m_buffer.mid(4, len); m_recvEdit->append("收到: " + QString(data)); // 移除已处理数据 m_buffer = m_buffer.mid(4 + len); } } private: QTcpServer *m_server; QTcpSocket *m_socket = nullptr; QTextEdit *m_recvEdit; QByteArray m_buffer; // 接收缓冲区 }; int main(int argc, char *argv[]) { QApplication a(argc, argv); TcpServer w; w.show(); return a.exec(); } #include "main.moc"

4. TCP 客户端（组包：添加长度头）

cpp

运行

#include <QApplication> #include <QMainWindow> #include <QTcpSocket> #include <QPushButton> #include <QLineEdit> #include <QVBoxLayout> #include <QByteArray> class TcpClient : public QMainWindow { Q_OBJECT public: TcpClient() { resize(400,200); m_socket = new QTcpSocket(this); m_edit = new QLineEdit; QPushButton *btnSend = new QPushButton("发送"); QVBoxLayout *lay = new QVBoxLayout; lay->addWidget(m_edit); lay->addWidget(btnSend); QWidget *cen = new QWidget; cen->setLayout(lay); setCentralWidget(cen); // 连接服务端 m_socket->connectToHost("127.0.0.1", 8888); connect(btnSend, &QPushButton::clicked, this, &TcpClient::sendMsg); } private slots: void sendMsg() { QString text = m_edit->text(); QByteArray data = text.toUtf8(); // 组包：前4字节长度 + 原始数据 quint32 len = data.size(); QByteArray pkg; pkg.append((char*)&len, 4); pkg.append(data); m_socket->write(pkg); m_edit->clear(); } private: QTcpSocket *m_socket; QLineEdit *m_edit; }; int main(int argc, char *argv[]) { QApplication a(argc, argv); TcpClient w; w.show(); return a.exec(); } #include "main.moc"

5. 粘包方案总结

长度头方案：二进制通信、协议交互首选，稳定性最强；
分隔符方案：HTTP、串口、文本指令场景使用；
必须设置接收缓冲区，循环拆包，保证每条消息完整解析。

第二部分：WebSocket 实时双向通信

WebSocket 基于 HTTP 握手，实现长连接、全双工实时通信，适合聊天室、物联网推送、网页 + Qt 交互。

1. 模块与类

模块：network
服务端：QWebSocketServer
客户端：QWebSocket

2. WebSocket 服务端

cpp

运行

#include <QApplication> #include <QMainWindow> #include <QWebSocketServer> #include <QWebSocket> #include <QTextEdit> #include <QVBoxLayout> class WsServer : public QMainWindow { Q_OBJECT public: WsServer() { resize(500,300); m_wsServer = new QWebSocketServer("WsServer", QWebSocketServer::NonSecureMode, this); m_edit = new QTextEdit; setCentralWidget(m_edit); if(m_wsServer->listen(QHostAddress::Any, 9999)) m_edit->append("WebSocket 服务端启动，端口9999"); connect(m_wsServer, &QWebSocketServer::newConnection, this, &WsServer::onNewConn); } private slots: void onNewConn() { QWebSocket *socket = m_wsServer->nextPendingConnection(); m_edit->append("客户端接入"); connect(socket, &QWebSocket::textMessageReceived, this, [=](const QString &msg){ m_edit->append("收到消息: " + msg); // 回显 socket->sendTextMessage("服务端已收到：" + msg); }); connect(socket, &QWebSocket::disconnected, socket, &QWebSocket::deleteLater); } private: QWebSocketServer *m_wsServer; QTextEdit *m_edit; }; int main(int argc, char *argv[]) { QApplication a(argc, argv); WsServer w; w.show(); return a.exec(); } #include "main.moc"

3. WebSocket 客户端

cpp

运行

#include <QApplication> #include <QMainWindow> #include <QWebSocket> #include <QLineEdit> #include <QPushButton> #include <QTextEdit> #include <QVBoxLayout> class WsClient : public QMainWindow { Q_OBJECT public: WsClient() { resize(400,300); m_ws = new QWebSocket; m_recvEdit = new QTextEdit; m_sendEdit = new QLineEdit; QPushButton *btnSend = new QPushButton("发送"); QVBoxLayout *lay = new QVBoxLayout; lay->addWidget(m_recvEdit); lay->addWidget(m_sendEdit); lay->addWidget(btnSend); QWidget *cen = new QWidget; cen->setLayout(lay); setCentralWidget(cen); // 连接服务端 m_ws->open(QUrl("ws://127.0.0.1:9999")); connect(m_ws, &QWebSocket::textMessageReceived, this, [=](const QString &msg){ m_recvEdit->append("服务端: " + msg); }); connect(btnSend, &QPushButton::clicked, this, &WsClient::sendMsg); } private slots: void sendMsg() { QString text = m_sendEdit->text(); m_ws->sendTextMessage(text); m_sendEdit->clear(); } private: QWebSocket *m_ws; QTextEdit *m_recvEdit; QLineEdit *m_sendEdit; }; int main(int argc, char *argv[]) { QApplication a(argc, argv); WsClient w; w.show(); return a.exec(); } #include "main.moc"