前言

QTcpSocket QUdpSocket 在多线程里的其中一种方式代码分享
说明一点：QTcpSocket QUdpSocket 都是基于 QAbstractSocket，都是异步调用，绝大多数据情况下是不需要使用多线程的，不会阻塞UI线程。

看官方说明就得知，在线程中使用waitFor**系列的阻塞函数是最简单的通信方式，但Qt官方有个警告：
在这里插入图片描述
注意:此函数在Windows上可能随机失败。如果您的软件要在Windows上运行，可以考虑使用事件循环和readyRead()信号。

所以在windows上，我这里写一个简单的线程客户端,同时有一个重要功能,断线自动重连,只要识别到服务器主动断开,或者本地网络出现问题等错误引起的断开,都会自动重连,代码并不完善,只是提供一个思路.

一、QTcpSocket

LinkTCP.h

class LinkTCP : public QThread{
	Q_OBJECT
public:
	LinkTCP()
	void close();
	void writeByte(const QByteArray& byte);
	void run() override;
signals:
	void receivecBytes(const QByteArray& byte);

private:
    QMutex            m_mutex;
    QList<QByteArray> m_list;
    QString m_ip;
    quint16 m_port;
    std::atomic_bool m_isConnected;
}

LinkTCP.cpp

void LinkTCP::close(){
    m_isConnected = false;
    requestInterruption();
    quit();
    wait();
}
void LinkTCP::writeByte(const QByteArray& byte){
	m_mutex.lock();
	m_list.append(byte)
	m_mutex.unlock();
}
void LinkTCP::run(){
	threadConnect();
}
void LinkTCP::threadConnect()
{
    m_mutex.lock();
    QString ip   = m_ip;
    quint16 port = m_port;
    m_mutex.unlock();
    while (!isInterruptionRequested()) {
        QTcpSocket socket;
        socket.connectToHost(ip, port);

        auto c1 = connect(&socket, &QTcpSocket::connected, this, [&]() {
            m_isConnected = true;
            quit();
        });
        auto c2 = connect(&socket, &QTcpSocket::errorOccurred, this, [&]() {
            m_isConnected = false;
            quit();
        });
        auto c3 = connect(&socket, &QTcpSocket::disconnected, this, [&]() {
            m_isConnected = false;
            quit();
        });
        auto c4 = connect(
            &socket, &QTcpSocket::readyRead, this,
            [&]() {
                auto byte_size = socket.bytesAvailable();
                if (byte_size > 0) {
                    QByteArray buffer;
                    buffer.resize(byte_size);
                    socket.read(buffer.data(), buffer.size());
                    emit receivecBytes(buffer);
                }
            },
            Qt::DirectConnection);

        do {
            exec();
            QMutexLocker l(&m_mutex);
            while (!m_list.isEmpty()) {
                socket.write(m_list.takeFirst());
            }
            l.unlock();
        } while (m_isConnected);

        disconnect(c1);
        disconnect(c2);
        disconnect(c3);
        disconnect(c4);
        socket.abort();
        socket.close();
    }
}

二、QUdpSocket

Udp 同Tcp的思路一样

void LinkUDP::threadConnect()
{
    bool m_isConnected = false;
    m_mutex.lock();
    QHostAddress ip(m_ip);
    quint16      port = m_port;
    LinkType     type = m_type;
    m_mutex.unlock();

    LOG_DEBUG() << ip << port;
    while (!isInterruptionRequested()) {
        QUdpSocket socket;
        if (!socket.bind(333, QUdpSocket::ShareAddress)) {
            LOG_DEBUG() << "error" << socket.errorString();
            msleep(1000);
            continue;
        }

        auto c1 = connect(&socket, &QUdpSocket::connected, this, [&]() {
            m_isConnected = true;
            quit();
        });
        auto c2 = connect(&socket, &QUdpSocket::errorOccurred, this, [&]() {
            m_isConnected = false;
            quit();
        });
        auto c3 = connect(&socket, &QUdpSocket::disconnected, this, [&]() {
            m_isConnected = false;
            quit();
        });
        auto c4 = connect(
            &socket, &QUdpSocket::readyRead, this,
            [&]() {
                LOG_DEBUG() << currentThreadId();
                while (socket.hasPendingDatagrams()) {
                    QByteArray buffer;
                    buffer.resize(socket.pendingDatagramSize());
                    QHostAddress sender;
                    quint16      sendPort;
                    int          len = socket.readDatagram(buffer.data(), buffer.size(), &sender, &sendPort);
                    LOG_DEBUG() << sender << sendPort;
                    if (len == -1)
                        break;
                    emit receivecBytes(buffer);
                }
            },
            Qt::DirectConnection);

        LOG_DEBUG() << currentThreadId();
        do {
            exec();

            m_mutex.lock();
            while (!m_data.isEmpty()) {
                socket.writeDatagram(m_data.takeFirst(), ip, port);
            }
            m_mutex.unlock();
        } while (m_isConnected);

        disconnect(c1);
        disconnect(c2);
        disconnect(c3);
        disconnect(c4);
        socket.abort();
        socket.close();
    }
}