【QT】TCP客户端网络连接

第一步：.pro工程文件添加
QT += network
第二步：.h文件添加代码

#ifndef TCPCLIENT_H
#define TCPCLIENT_H
#include <QException>
#include <QDebug>
#include <QTcpSocket>
#include <QHostAddress>

class TCPClient: public QObject
{
    Q_OBJECT
public:
    TCPClient();
    bool openTcpClient(QString ip, qint16 port);
    void closeTcpClient();
    bool sendData(QString msg);
    bool getConnectStatus();
private:
    void readData();
private:
    QTcpSocket *socket = nullptr;
    qint32 MAX_BUFFER = 1024 * 10;
signals:
    //信号没有返回值，可以有参数,信号函数不需要定义，只需要声明
    void pushClient_singal(QByteArray buffer, qint64 length);
};

#endif // TCPCLIENT_H

第三步:.cpp文件添加代码

#include "tcpclient.h"

TCPClient::TCPClient()
{
}

// 打开网络连接
bool TCPClient::openTcpClient(QString ip, qint16 port)
{
    try {
        closeTcpClient();
        // 创建通信的套接字
        socket = new QTcpSocket(this);
        socket->abort();                 //取消原有连接
        // 接受到服务端消息
        connect(socket, &QTcpSocket::readyRead, this, [ = ]() {
            readData();
        });
        // 服务器端断开连接
        connect(socket, &QTcpSocket::disconnected, this, [ = ]() {
            closeTcpClient();
        });
        // 检测连接状态
        connect(socket, &QTcpSocket::connected, this, [ = ]() {
        });
        socket->connectToHost(QHostAddress(ip), port);
        // 等待连接成功
        if(socket->waitForConnected()) {
            return true;
        }
    } catch (std::exception ex) {
        qCritical() << "打开网络连接失败:" << ex.what();
    }
    return false;
}
// 关闭网络
void TCPClient::closeTcpClient()
{
    try {
        if(socket != NULL&&socket->state()) {
            socket->disconnectFromHost();
            socket->abort();
            socket->close();
            socket->deleteLater();
            socket = nullptr;
        }
    } catch (std::exception ex) {
        qCritical() << "关闭网络连接失败:" << ex.what();
    }
}
// 发送数据
bool TCPClient::sendData(QString msg)
{
    try {
        if(socket != nullptr && socket->isOpen()) {
            // (msg.toUtf8();//转换成utf8格式的字节流发送
            // 按十六进制编码发送
            QByteArray byte = QByteArray::fromHex (msg.toLatin1().data());//按十六进制编码发送
            socket->write(byte);
            //判断是否写入成功
            bool iswrite = socket->waitForBytesWritten();
            if (iswrite) {
                //写入成功
                return true;
            } else {
                //没有写入成功
                return false;
            }
        }
    } catch (std::exception ex) {
        qCritical() << "客户端发送失败:" << ex.what();
    }
    return false;
}

// 获取连接状态
bool TCPClient::getConnectStatus()
{
    return socket->state();
}
// 接收数据
void TCPClient::readData()
{
    try {
        // 设置每次读取最大缓存数据
        QByteArray receiveByte = socket->read(MAX_BUFFER);
        // 一次读取全部缓存数据
        //QByteArray receiveByte = m_socket->readAll();
        if(receiveByte.count() > 0) {
            pushClient_singal(receiveByte, receiveByte.count());
        } else {
            qInfo() << "读取不到数据";
        }
    } catch (std::exception ex) {
        qCritical() << "读取数据失败:" << ex.what();
    }
}