服务器
使用前要在cmake工程文件里边添加network模块
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| find_package(Qt5 COMPONENTS core network REQUIRED)
target_link_libraries(${PROJECT_NAME} Qt5::Core Qt5::Network)
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TCP通信服务器的核心类是QTcpServer，头文件同名
使用也特别简单，先绑定IP地址和端口号，listen的返回结果如果是false则端口号有可能被占用，Windows上建议用netstat -aon | findstr "9090"事先看一下端口占用情况，Linux下则是用netstat -tlp | grep 9090
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| QTcpServer server;
bool ret = server.listen(QHostAddress("127.0.0.1"), 9090);
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编写newConnection信号对应的槽函数，服务器通过nextPendingConnection接口获取已建立的socket，然后对socket进行读写
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| QObject::connect(&server, &QTcpServer::newConnection, [&]() {
auto &&socket = server.nextPendingConnection();
auto timer = new QTimer();
QObject::connect(timer, &QTimer::timeout, [&, socket]() {
socket->write(QByteArray("hello world"));
});
timer->start(1000);
QObject::connect(socket, &QTcpSocket::readyRead, [&, socket]() {
qDebug() << "Server : " << socket->readAll();
});
});
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客户端
客户端同理，使用前也要在cmake工程文件里边添加network模块
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| find_package(Qt5 COMPONENTS core network REQUIRED)
target_link_libraries(${PROJECT_NAME} Qt5::Core Qt5::Network)
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客户端使用QTcpSocket进行TCP通信
调用connectToHost接口建立服务器通信连接
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| QTcpSocket socket;
socket.connectToHost(QHostAddress("127.0.0.1"), 9090);
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需要处理几个跟连接相关的信号：connected、disconnected、readyRead
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QObject::connect(&socket, &QTcpSocket::connected, [&]() {
timer->start(1000);
qDebug() << "Client connected server";
});
QObject::connect(&socket, &QTcpSocket::disconnected, [&]() {
qDebug() << "Client disconnected server";
});
QObject::connect(&socket, &QTcpSocket::readyRead, [&]() {
qDebug() << "Client : " << socket.readAll();
});
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基类QIODevice的读写接口
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| qint64 read(char *data, qint64 maxlen);
QByteArray read(qint64 maxlen);
QByteArray readAll();
qint64 readLine(char *data, qint64 maxlen);
QByteArray readLine(qint64 maxlen = 0);
qint64 write(const char *data, qint64 len);
qint64 write(const char *data);
inline qint64 write(const QByteArray &data)
{ return write(data.constData(), data.size()); }
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结果
- 以上的服务器和客户端在互相给对方发hello world数据
- QTcpServer那里巧妙抽象了QTcpSocket的操作方式，客户端和服务器都是对QTcpSocket读写
