Qt网络编程实现TCP通信

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QTcpServer>
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE

class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();
private slots:
    void onNewConnect();    //客户端新的连接请求处理
    void onSendBackMsg();   //反馈信息给客户端新的连接
    void onReadMsg();       //服务端读取客户端发来的数据
private:
    Ui::Widget *ui;
    QTcpServer* m_tcpServer;    //tcp服务端
    QTcpSocket* m_tcpSocket;    //tcp套接字
};
#endif // WIDGET_H

#include "widget.h"
#include "ui_widget.h"
#include <QTcpSocket>
Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    m_tcpServer=new QTcpServer(this);
    //服务端监听客户端发来的请求
    if(!m_tcpServer->listen(QHostAddress::AnyIPv4,6666)){
        qDebug()<<m_tcpServer->errorString();
        close();
    }
    connect(m_tcpServer,&QTcpServer::newConnection,this,&Widget::onNewConnect);
    connect(m_tcpServer,&QTcpServer::newConnection,this,&Widget::onSendBackMsg);
}

Widget::~Widget()
{
    delete ui;
}

void Widget::onNewConnect()
{
    //当前连接的客户端
    m_tcpSocket=m_tcpServer->nextPendingConnection();
    //断开连接
    connect(m_tcpSocket,&QTcpSocket::disconnected,
            m_tcpSocket,&QTcpSocket::deleteLater);
    //socket有数据时会发送readyRead信号
    connect(m_tcpSocket,&QTcpSocket::readyRead,
            this,&Widget::onReadMsg);
}
void Widget::onSendBackMsg()
{
    QString str="你好，客户端！";
    m_tcpSocket->write(str.toUtf8());
    ui->label->setText("反馈数据成功！");

}

void Widget::onReadMsg()
{
    //服务端将客户端发来的数据显示到标签上
    QByteArray bt=m_tcpSocket->readAll();
    ui->readLabel->setText(bt);
}

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QTcpSocket>

QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE

class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();
private slots:
    void onReadMessage();   //处理服务端反馈的数据
    void onDisplayError(QAbstractSocket::SocketError e);    //打印错误信息
    void on_connectBtn_clicked();   //点击连接按钮响应信号的槽函数
    void on_sendBtn_clicked();  //点击发送按钮响应的槽函数
private:
    Ui::Widget *ui;
    QTcpSocket* m_tcpSocket;    //tcp客户端
};
#endif // WIDGET_H

#include "widget.h"
#include "ui_widget.h"
#include <QAbstractSocket>
const int gTcpPort=6666;
Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    m_tcpSocket=new QTcpSocket(this);
    //socket有数据来了，做处理
    connect(m_tcpSocket,&QTcpSocket::readyRead,
            this,&Widget::onReadMessage);
    connect(m_tcpSocket,SIGNAL(QAbstractSocket::SocketError),
            this,SLOT(onDisplayError(QAbstractSocket::SocketError)));
    //设置客户端连接默认的主机地址及端口号
    ui->hostLineEdit->setText("127.0.0.1");
    ui->portLineEdit->setText(QString::number(gTcpPort));
}

Widget::~Widget()
{
    delete ui;
}

void Widget::onReadMessage()
{
    QByteArray bt;
    bt.resize(m_tcpSocket->bytesAvailable());
    m_tcpSocket->read(bt.data(),bt.size());
    //将客户端反馈的数据显示到标签上
    ui->recvLabel->setText(bt);
}

void Widget::onDisplayError(QAbstractSocket::SocketError e)
{
    qDebug()<<"SocketError:"<<e<<endl
           <<m_tcpSocket->errorString();
}

void Widget::on_connectBtn_clicked()
{
    m_tcpSocket->abort();
    //连接服务端
    m_tcpSocket->connectToHost(ui->hostLineEdit->text(),
                               ui->portLineEdit->text().toInt());
}

void Widget::on_sendBtn_clicked()
{
    m_tcpSocket->write(ui->sendEdit->text().toUtf8());
    m_tcpSocket->flush();//清空缓冲区
}