QT学习之路六（QT的tcp传输）

小咪咪 2022-07-12 08:29 215阅读 0赞

这几天一直在做银行的管理系统，包括职工的登陆注册以及客户的开户转账存取款等功能，这几天天天通宵也写的差不多了，还剩下最后一个功能，交易记录的管理，差不多明天应该就能结束了。

这两天为了做这个东西，我把qt的网络模块初学了一下，学了一下qt的tcp传输，实现了服务器与客户端的通信。但是，在做的时候，我本来是打算做一个循环并发的服务器，但测试了一下后，突然发现，这个服务器根本不用开线程，它一直在工作，在一个客户端连接后，它就通过信号与槽函数，直接去处理，处理完后再返回，这样做，在连接数少的时候，确实和并发服务器差不多，但是做一个假设，假设有1000多台客户端连接的话，瞬间崩溃了，但我也不懂在哪边开线程合适，Linux中的话服务器在连接到后就应该开辟线程，但是qt中服务器在得到连接后直接去处理槽函数了，所以想了很久，还是不懂在哪边开辟线程，最终还是没有做出来，不过几十台的话处理起来应该没有什么问题（安慰自己。。）。

下面的代码（没有开线程）：

/********************************************************************************
    ** Form generated from reading UI file 'client.ui'
    **
    ** Created: Thu Feb 16 16:09:39 2017
    **      by: Qt User Interface Compiler version 4.8.1
    **
    ** WARNING! All changes made in this file will be lost when recompiling UI file!
    ********************************************************************************/
    
    #ifndef UI_CLIENT_H
    #define UI_CLIENT_H
    
    #include <QtCore/QVariant>
    #include <QtGui/QAction>
    #include <QtGui/QApplication>
    #include <QtGui/QButtonGroup>
    #include <QtGui/QDialog>
    #include <QtGui/QHeaderView>
    #include <QtGui/QLabel>
    #include <QtGui/QLineEdit>
    #include <QtGui/QPushButton>
    
    QT_BEGIN_NAMESPACE
    
    class Ui_client
    {
    public:
        QLabel *label;
        QLabel *label_2;
        QLabel *messagelabel;
        QLineEdit *hostlineEdit;
        QLineEdit *portlineEdit;
        QPushButton *connect;
    
        void setupUi(QDialog *client)
        {
            if (client->objectName().isEmpty())
                client->setObjectName(QString::fromUtf8("client"));
            client->resize(400, 300);
            label = new QLabel(client);
            label->setObjectName(QString::fromUtf8("label"));
            label->setGeometry(QRect(60, 70, 71, 31));
            label_2 = new QLabel(client);
            label_2->setObjectName(QString::fromUtf8("label_2"));
            label_2->setGeometry(QRect(60, 130, 71, 31));
            messagelabel = new QLabel(client);
            messagelabel->setObjectName(QString::fromUtf8("messagelabel"));
            messagelabel->setGeometry(QRect(80, 190, 171, 61));
            hostlineEdit = new QLineEdit(client);
            hostlineEdit->setObjectName(QString::fromUtf8("hostlineEdit"));
            hostlineEdit->setGeometry(QRect(130, 80, 113, 20));
            portlineEdit = new QLineEdit(client);
            portlineEdit->setObjectName(QString::fromUtf8("portlineEdit"));
            portlineEdit->setGeometry(QRect(130, 140, 113, 20));
            connect = new QPushButton(client);
            connect->setObjectName(QString::fromUtf8("connect"));
            connect->setGeometry(QRect(260, 240, 75, 23));
    
            retranslateUi(client);
    
            QMetaObject::connectSlotsByName(client);
        } // setupUi
    
        void retranslateUi(QDialog *client)
        {
            client->setWindowTitle(QApplication::translate("client", "client", 0, QApplication::UnicodeUTF8));
            label->setText(QApplication::translate("client", "\344\270\273\346\234\272", 0, QApplication::UnicodeUTF8));
            label_2->setText(QApplication::translate("client", "\347\253\257\345\217\243", 0, QApplication::UnicodeUTF8));
            messagelabel->setText(QApplication::translate("client", "\346\216\245\346\224\266\345\210\260\347\232\204\344\277\241\346\201\257", 0, QApplication::UnicodeUTF8));
            connect->setText(QApplication::translate("client", "\350\277\236\346\216\245", 0, QApplication::UnicodeUTF8));
        } // retranslateUi
    
    };
    
    namespace Ui {
        class client: public Ui_client {};
    } // namespace Ui
    
    QT_END_NAMESPACE
    
    #endif // UI_CLIENT_H

#ifndef CLIENT_H
    #define CLIENT_H
    
    #include <QDialog>
    #include <QAbstractSocket>
    #include <QTcpSocket>
    #include <QString>
    
    namespace Ui {
    class client;
    }
    
    class client : public QDialog
    {
        Q_OBJECT
        
    public:
        explicit client(QWidget *parent = 0);
        ~client();
        
    private:
        Ui::client *ui;
        QTcpSocket *tcpsocket;
        QString  message;
        quint16 blocksize;
    private slots:
        void newconnect();
        void readmessage();
        void displayreeoe(QAbstractSocket::SocketError);
        void on_connect_clicked();
    };
    
    #endif // CLIENT_H

#include "client.h"
    #include "ui_client.h"
    #include <QtNetwork>
    
    client::client(QWidget *parent) :
        QDialog(parent),
        ui(new Ui::client)
    {
        ui->setupUi(this);
        tcpsocket = new QTcpSocket(this);
        connect(tcpsocket, SIGNAL(readyRead()), this, SLOT(readmessage()));
        connect(tcpsocket, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(displayreeoe(QAbstractSocket::SocketError)));
    
    }
    
    client::~client()
    {
        delete ui;
    }
    
    void client::newconnect()
    {
        blocksize = 0;
        tcpsocket->abort();
        tcpsocket->connectToHost(ui->hostlineEdit->text(), ui->portlineEdit->text().toInt());
    }
    
    void client::readmessage()
    {
        QDataStream in(tcpsocket);
        in.setVersion(QDataStream::Qt_4_6);
        if(blocksize == 0)
        {
            if(tcpsocket->bytesAvailable() < (int)sizeof(quint16))
            {
                return;
            }
            in>>blocksize;
        }
        if(tcpsocket->bytesAvailable() < blocksize)
        {
            return;
        }
        in>>message;
        ui->messagelabel->setText(message);
    }
    
    void client::displayreeoe(QAbstractSocket::SocketError)
    {
        qDebug()<<tcpsocket->errorString();
    }
    
    void client::on_connect_clicked()
    {
        newconnect();
    }

#include <QtGui/QApplication>
    #include "client.h"
    
    int main(int argc, char *argv[])
    {
        QApplication a(argc, argv);
        client w;
        w.show();
        
        return a.exec();
    }

/********************************************************************************
    ** Form generated from reading UI file 'server.ui'
    **
    ** Created: Thu Feb 16 15:41:59 2017
    **      by: Qt User Interface Compiler version 4.8.1
    **
    ** WARNING! All changes made in this file will be lost when recompiling UI file!
    ********************************************************************************/
    
    #ifndef UI_SERVER_H
    #define UI_SERVER_H
    
    #include <QtCore/QVariant>
    #include <QtGui/QAction>
    #include <QtGui/QApplication>
    #include <QtGui/QButtonGroup>
    #include <QtGui/QDialog>
    #include <QtGui/QHeaderView>
    #include <QtGui/QLabel>
    
    QT_BEGIN_NAMESPACE
    
    class Ui_server
    {
    public:
        QLabel *label;
    
        void setupUi(QDialog *server)
        {
            if (server->objectName().isEmpty())
                server->setObjectName(QString::fromUtf8("server"));
            server->resize(400, 300);
            label = new QLabel(server);
            label->setObjectName(QString::fromUtf8("label"));
            label->setGeometry(QRect(70, 40, 121, 61));
    
            retranslateUi(server);
    
            QMetaObject::connectSlotsByName(server);
        } // setupUi
    
        void retranslateUi(QDialog *server)
        {
            server->setWindowTitle(QApplication::translate("server", "server", 0, QApplication::UnicodeUTF8));
            label->setText(QApplication::translate("server", "\347\255\211\345\276\205\350\277\236\346\216\245....", 0, QApplication::UnicodeUTF8));
        } // retranslateUi
    
    };
    
    namespace Ui {
        class server: public Ui_server {};
    } // namespace Ui
    
    QT_END_NAMESPACE
    
    #endif // UI_SERVER_H

#ifndef SERVER_H
    #define SERVER_H
    
    #include <QDialog>
    #include <QTcpServer>
    
    namespace Ui {
    class server;
    }
    
    class server : public QDialog
    {
        Q_OBJECT
        
    public:
        explicit server(QWidget *parent = 0);
        ~server();
        
    private:
        Ui::server *ui;
        QTcpServer *tcp_server;
    public slots:
        void sendmassage();
    };
    
    #endif // SERVER_H

#include "server.h"
    #include "ui_server.h"
    #include <QtNetwork>
    
    server::server(QWidget *parent) :
        QDialog(parent),
        ui(new Ui::server)
    {
        ui->setupUi(this);
        tcp_server = new QTcpServer(this);
        if(! tcp_server->listen(QHostAddress::LocalHost, 6666))
        {
            qDebug()<<tcp_server->errorString();
            close();
        }
        connect(tcp_server, SIGNAL(newConnection()), this, SLOT(sendmassage()));
    }
    
    server::~server()
    {
        delete ui;
    }
    
    void server::sendmassage()
    {
        QByteArray block;
        QDataStream out(&block, QIODevice::WriteOnly);
    
        out.setVersion(QDataStream::Qt_4_0);
        out<<(quint16)0;
        out<<tr("hello tcp!!!");
        out.device()->seek(0);
        out<<(quint16)(block.size()-sizeof(quint16));
    
        QTcpSocket *cfd = tcp_server->nextPendingConnection();
        connect(cfd, SIGNAL(disconnected()), cfd, SLOT(deleteLater()));
        cfd->write(block);
        cfd->disconnectFromHost();
        ui->label->setText("send message successful!");
    }

#include <QtGui/QApplication>
    #include "server.h"
    
    int main(int argc, char *argv[])
    {
        QApplication a(argc, argv);
        server w;
        w.show();
        
        return a.exec();
    }