QT中的服务器与客户端

一、前言

本文主要讲讲QT中服务器与客户端的使用方法，QT已经封装好了，调用相应类直接访问即可。本文以QT中的QT中的TCP为例子，讲下使用方法以及线程中使用。

二、正文

2.1 Sever的使用方法

2.1.1 思路

QT中Sever使用的时候大致步骤为：

1、创建监听的服务器对象

2、监听到数据信号，创建QTcpSocket的套接字对象

3、检测是否可以接收数据

4、信息发送，查看数据发送是否正常

总的来说，就是先确定要监听的地址与端口，然后数据在套接字中，套接字在QT中是QTcpSocket

封装的类，直接用就行，最后通过套接字接收数据或者发送数据即可。

2.1.2 代码示例

#ifndef WIDGET_H
#define WIDGET_H#include <QWidget>
#include <QTcpServer>
#include <QTcpSocket>QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACEclass Widget : public QWidget
{Q_OBJECTpublic:Widget(QWidget *parent = nullptr);~Widget();private:Ui::Widget *ui;QTcpServer *m_server;QTcpSocket *m_tcp;
};
#endif // WIDGET_H

#include "widget.h"
#include "ui_widget.h"Widget::Widget(QWidget *parent): QWidget(parent), ui(new Ui::Widget)
{ui->setupUi(this);ui->lineEdit_port->setText("8888");//创建监听的服务器对象m_server = new QTcpServer(this);connect(ui->pushButton_listen, &QPushButton::clicked, this, [=](){m_server->listen(QHostAddress::Any, ui->lineEdit_port->text().toInt());ui->pushButton_listen->setDisabled(true);});//监听到数据信号，创建QTcpSocket的套接字对象connect(m_server, &QTcpServer::newConnection, this, [=](){m_tcp = m_server->nextPendingConnection();//检测是否可以接收数据connect(m_tcp, &QTcpSocket::readyRead, this, [=](){QByteArray data = m_tcp->readAll();ui->textEdit_historymsg->append("客户端说： " + data);});});//信息发送connect(ui->pushButton_send, &QPushButton::clicked, this, [=](){QString msg = ui->textEdit_sendmsg->toPlainText();m_tcp->write(msg.toUtf8());ui->textEdit_historymsg->append("服务器说： " + msg);});}Widget::~Widget()
{delete ui;
}

2.1.3 细节讲解

创建服务器对象QTcpServer，对象有监听的方法listen。

监听的地址设置所有即可访问你电脑可以收到的所有地址，可以用win+R进入cmd查看有哪些，比如：

获取到新的连接后，将下一个挂起的连接作为已连接的QTcpSocket对象返回

准备读取信号有了后即可开始读取套接字内的数据。

2.1.4 演示

监听成功

2.2 Client的使用方法

2.2.1 思路

QT中Client使用的时候大致步骤为：

1、创建Socket对象,连接服务器

2、数据交互

3、根据需求断开连接

总体来说很简单，套接字连接好服务器的地址与端口即可，前提是服务器开启了，不然连接会失败。

2.2.2 代码示例

#ifndef WIDGET_H
#define WIDGET_H#include <QWidget>
#include <QTcpSocket>QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACEclass Widget : public QWidget
{Q_OBJECTpublic:Widget(QWidget *parent = nullptr);~Widget();private:Ui::Widget *ui;QTcpSocket *m_socket;
};
#endif // WIDGET_H

#include "widget.h"
#include "ui_widget.h"#include <QHostAddress>Widget::Widget(QWidget *parent): QWidget(parent), ui(new Ui::Widget)
{ui->setupUi(this);ui->lineEdit_address->setText("192.168.2.24");ui->lineEdit_connect->setText("8888");//创建Socket对象,连接服务器m_socket = new QTcpSocket(this);connect(ui->pushButton_connect, &QPushButton::clicked, this, [=](){m_socket->connectToHost(QHostAddress(ui->lineEdit_address->text()), ui->lineEdit_connect->text().toInt());ui->pushButton_connect->setDisabled(true);ui->pushButton_close->setEnabled(true);});//断开连接connect(ui->pushButton_close, &QPushButton::clicked, this, [=](){m_socket->close();ui->pushButton_connect->setEnabled(true);ui->pushButton_close->setDisabled(true);});//数据交互connect(m_socket, &QTcpSocket::connected, this, [=](){ui->textEdit_history->append("服务器连接成功！！！！");});connect(m_socket, &QTcpSocket::readyRead, this, [=](){ui->textEdit_history->append("服务器说： " + m_socket->readAll());});connect(m_socket, &QTcpSocket::disconnected, this, [=](){ui->textEdit_history->append("服务器断开连接！！！！");});connect(ui->pushButton_send, &QPushButton::clicked, this, [=](){m_socket->write(ui->textEdit_send->toPlainText().toUtf8());ui->textEdit_history->append("客户端说： " + ui->textEdit_send->toPlainText().toUtf8());});
}Widget::~Widget()
{delete ui;
}

2.2.3 细节讲解

没啥可讲的，QT都封装好了，连接好就能直接用，比串口的请求响应简单方便多了。

2.2.4 演示

注意，先开启服务器，然后才能使用，局域网可以内部使用，外部使用需要申请IP。

2.3 线程中的使用

在实际项目中，数据的部分大多是写进线程的，关于线程的了解在前文中有讲述，需要的朋友可以自行查阅。

下面以文件从客户端传到服务器为例：

2.3.1 代码示例

2.3.1.1 Sever

#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QMainWindow>
#include <QTcpServer>QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACEclass MainWindow : public QMainWindow
{Q_OBJECTpublic:MainWindow(QWidget *parent = nullptr);~MainWindow();private slots:void on_pushButton_listen_clicked();private:Ui::MainWindow *ui;QTcpServer* m_server;};
#endif // MAINWINDOW_H

#ifndef ACCEPTFILE_H
#define ACCEPTFILE_H#include <QObject>
#include <QThread>
#include <QTcpSocket>class acceptfile : public QThread
{Q_OBJECT
public:explicit acceptfile(QTcpSocket* tcp, QThread *parent = nullptr);signals:void over();protected:void run() override;private:QTcpSocket* m_tcp;};#endif // ACCEPTFILE_H

#include "mainwindow.h"
#include "ui_mainwindow.h"#include "acceptfile.h"#include <QMessageBox>MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow)
{ui->setupUi(this);//创建服务器对象m_server = new QTcpServer(this);//创建套接字connect(m_server, &QTcpServer::newConnection, this, [=](){QTcpSocket* tcp = m_server->nextPendingConnection();//创建子线程acceptfile* subthread = new acceptfile(tcp);subthread->start();//释放资源connect(subthread, &acceptfile::over, this, [=](){subthread->quit();subthread->wait();subthread->deleteLater();QMessageBox::information(this, "文件接收", "文件接收完毕！！！！！！！");});});}MainWindow::~MainWindow()
{delete ui;
}void MainWindow::on_pushButton_listen_clicked()
{m_server->listen(QHostAddress::Any, ui->lineEdit_port->text().toUShort());
}

#include "acceptfile.h"#include <QFile>acceptfile::acceptfile(QTcpSocket* tcp, QThread *parent) : QThread(parent)
{m_tcp = tcp;
}void acceptfile::run()
{//创建文件对象，保存客户端发送过来的文件内容QFile* file = new QFile("C:/Users/EDY/Desktop/QTtest/recv.txt");file->open(QFile::WriteOnly);//读取套接字socket的内容connect(m_tcp, &QTcpSocket::readyRead, this, [=](){static int total = 0;static int count = 0;if(count == 0){m_tcp->read((char*)&total, 4);}//读出剩余数据QByteArray all = m_tcp->readAll();count += all.size();file->write(all);//判断是否接收完毕if(total == count){m_tcp->close();m_tcp->deleteLater();file->close();file->deleteLater();emit over();}});//进入事件循环exec();
}

2.3.1.2 Client

#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include <QMainWindow>#include <QThread>QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACEclass MainWindow : public QMainWindow
{Q_OBJECTpublic:MainWindow(QWidget *parent = nullptr);~MainWindow();signals:void startconnect(unsigned short, QString);void sendFile(QString path);private slots:void on_connectserver_btn_clicked();void on_file_btn_clicked();void on_send_btn_clicked();private:Ui::MainWindow *ui;};
#endif // MAINWINDOW_H

#ifndef SENDFILE_H
#define SENDFILE_H#include <QObject>
#include <QTcpSocket>class sendfile : public QObject
{Q_OBJECT
public:explicit sendfile(QObject *parent = nullptr);//连接服务器void connectServer(unsigned short address, QString ip);//发送文件void sendFile(QString path);signals:void connectOK();void gameover();void curpercent(int);private:QTcpSocket* m_tcp;};#endif // SENDFILE_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "sendfile.h"#include <QFileDialog>
#include <QMessageBox>MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow)
{ui->setupUi(this);ui->port->setText("8888");ui->IP->setText("192.168.2.24");ui->progressBar->setRange(0, 100);ui->progressBar->setValue(0);//创建线程对象QThread* thrd = new QThread;//创建任务sendfile* worker = new sendfile;//将work放入子线程worker->moveToThread(thrd);//连接服务器connect(this, &MainWindow::startconnect, worker, &sendfile::connectServer);//连接文件发送connect(this, &MainWindow::sendFile, worker, &sendfile::sendFile);//处理连接服务器的子线程数据connect(worker, &sendfile::connectOK, this, [=](){QMessageBox::information(this, "连接服务器",  "连接成功！！！！");});connect(worker, &sendfile::gameover, this, [=](){//资源释放thrd->quit();thrd->wait();worker->deleteLater();thrd->deleteLater();});//处理选择文件发送子线程数据connect(worker, &sendfile::curpercent, ui->progressBar, &QProgressBar::setValue);//线程开始thrd->start();
}MainWindow::~MainWindow()
{delete ui;
}void MainWindow::on_connectserver_btn_clicked()
{QString ip = ui->IP->text();unsigned short port = ui->port->text().toUShort();emit startconnect(port, ip);
}void MainWindow::on_file_btn_clicked()
{QString path = QFileDialog::getOpenFileName();if(path.isEmpty()){QMessageBox::warning(this, "打开文件", "选择的文件路径不能为空！！");return;}ui->file->setText(path);
}void MainWindow::on_send_btn_clicked()
{emit sendFile(ui->file->text());
}

#include "sendfile.h"#include <QFile>
#include <QFileInfo>sendfile::sendfile(QObject *parent) : QObject(parent)
{}void sendfile::connectServer(unsigned short address, QString ip)
{m_tcp = new QTcpSocket;m_tcp->connectToHost(ip, address);connect(m_tcp, &QTcpSocket::connected, this, &sendfile::connectOK);connect(m_tcp, &QTcpSocket::disconnected, this, [=](){m_tcp->close();m_tcp->deleteLater();emit gameover();});
}void sendfile::sendFile(QString path)
{QFile file(path);QFileInfo info(path);int filesize = info.size();file.open(QFile::ReadOnly);while (!file.atEnd()){static int num = 0;if(num == 0){m_tcp->write((char*)&filesize, 4);}QByteArray line = file.readLine();num += line.size();int percent = (num * 100 / filesize);emit curpercent(percent);m_tcp->write(line);}
}