线程中的QTcpSocket通信

Question

我正在制作两个应用程序：一个是服务器，一个是客户端。服务器使用QTcpServer和QThread来监听客户端。客户端使用QThread与服务器建立连接。 服务器和客户端成功连接，但问题是它们之间如何进行数据通信。在服务器端，当连接新客户端时，我放置了一行，使用 socket->write("hello") 向客户端发送数据，但客户端没有收到它。 “没有收到”的推测是基于在客户端调用 QDebug 时没有编写任何内容。 另外，我想问如何使客户端线程始终准备好从服务器接收数据，但有时可以在使用 PushButton 时用于将数据发送到服务器。 任何帮助将不胜感激。

客户端 main.cpp（使用小部件）

#include "mainwindow.h"
#include "ui_mainwindow.h"

#include "tcpthread.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_pushButton_clicked()
{
    TcpThread *tcpThread = new TcpThread(this);
    connect(tcpThread, SIGNAL(finished()), tcpThread, SLOT(deleteLater()));
    tcpThread->start();
}

客户端tcpthread.h

#ifndef TCPTHREAD_H
#define TCPTHREAD_H

#include <QThread>
#include <QTcpSocket>

class TcpThread : public QThread
{
    Q_OBJECT
public:
    explicit TcpThread(QObject *parent = 0);
    void run();
signals:
    void error(QTcpSocket::SocketError socketError);
public slots:
    void readyRead();
    void disconnected();
private:
    void processMessage(QByteArray message);
    QTcpSocket *socket;
    qintptr socketDescriptor;
    QByteArray data;
};

#endif // TCPTHREAD_H

客户端tcpthread.cpp

#include "tcpthread.h"

TcpThread::TcpThread(QObject *parent) :
    QThread(parent)
{
}

void TcpThread::run()
{
    qDebug() << "Thread started";
    socket = new QTcpSocket();
    connect(socket, SIGNAL(readyRead()), this, SLOT(readyRead()), Qt::DirectConnection);
    connect(socket, SIGNAL(disconnected()), this, SLOT(disconnected()));
    socket->connectToHost("127.0.0.1",1234);
    exec();
}

void TcpThread::readyRead()
{
    data = socket->readAll();
    while(!data.contains('\n'))
    {
        socket->waitForReadyRead();
        data += socket->readAll();
    }
    int bytes = data.indexOf('\n')+1;
    QByteArray message = data.left(bytes);
    data = data.mid(bytes);
    qDebug() << socketDescriptor << " : " << message;
    processMessage(message);
}

void TcpThread::disconnected()
{
    qDebug() << socketDescriptor << " disconnected";
    socket->deleteLater();
    exit(0);
}

void TcpThread::processMessage(QByteArray message)
{
    qDebug() << message << " processed";
}

服务器端main.cpp

#include "tcpserver.h"
#include <QCoreApplication>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    TcpServer tcpServer;
    tcpServer.startServer();

    return a.exec();
}

服务器端tcpthread.h

#ifndef TCPTHREAD_H
#define TCPTHREAD_H

#include <QThread>
#include <QTcpSocket>
#include <QDebug>

class TcpThread : public QThread
{
    Q_OBJECT
public:
    explicit TcpThread(qintptr ID, QObject *parent = 0);
    void run();
signals:
    void error(QTcpSocket::SocketError socketError);
public slots:
    void readyRead();
    void disconnected();
private:
    void processMessage(QByteArray message);
    QTcpSocket *socket;
    qintptr socketDescriptor;
    QByteArray data;
};

#endif // TCPTHREAD_H

服务器端tcpthread.cpp #include“tcpthread.h”

TcpThread::TcpThread(qintptr ID, QObject *parent) :
    QThread(parent)
{
    this->socketDescriptor = ID;
}

void TcpThread::run()
{
    qDebug() << "Thread started";
    socket = new QTcpSocket();
    if(!socket->setSocketDescriptor(this->socketDescriptor))
    {
        emit error(socket->error());
        return;
    }
    connect(socket, SIGNAL(readyRead()), this, SLOT(readyRead()), Qt::DirectConnection);
    connect(socket, SIGNAL(disconnected()), this, SLOT(disconnected()));
    qDebug() << socketDescriptor << " connected";
    socket->write("hello");
    exec();
}

void TcpThread::readyRead()
{
    data = socket->readAll();
    while(!data.contains('\n'))
    {
        socket->waitForReadyRead();
        data += socket->readAll();
    }
    int bytes = data.indexOf('\n')+1;
    QByteArray message = data.left(bytes);
    data = data.mid(bytes);
    qDebug() << socketDescriptor << " : " << message;
    processMessage(message);
    //socket->write(data);
}

void TcpThread::disconnected()
{
    qDebug() << socketDescriptor << " disconnected";
    socket->deleteLater();
    exit(0);
}

void TcpThread::processMessage(QByteArray message)
{
    qDebug() << message << " processed";
}

Answer 1

void TcpThread::readyRead()
{
    data = socket->readAll();
    while(!data.contains('\n'))
    {
        socket->waitForReadyRead();
        data += socket->readAll();
    }
    int bytes = data.indexOf('\n')+1;
    QByteArray message = data.left(bytes);
    data = data.mid(bytes);
    qDebug() << socketDescriptor << " : " << message;
    processMessage(message);
    //socket->write(data);
}

在 TcpThread 的 readRead() 槽中，您无法调用 waitForReadyRead()。

来自 https://doc.qt.io/qt-6/qiodevice.html#readyRead：

readyRead() 不是递归发出的；如果你重新进入事件循环 或者在连接到readyRead()的槽内调用waitForReadyRead() 信号，该信号不会被重新发送（尽管 waitForReadyRead() 可能仍返回 true）。