Qt 基于TCP的Socket编程

1、在工程文件中加入QT += network

2、服务器除了使用到了QTcpSocket类，还需要用到QTcpSever类

（1）创建QTcpSever对象

tcpServer = new QTcpServer(this);  

2）监听端口

tcpServer->listen(QHostAddress::LocalHost, 30000)  

（3） 当服务器被客户端访问时，会发出newConnection()信号，因此为该信号添加槽函数，并用一个QTcpSocket对象接受客户端访问

connect(tcpServer, &QTcpServer::newConnection,  
            this, &MainWindow::sendMessage);  

4）获取客户端连接

// 获取已经建立的连接的套接字  
clientConnection = tcpServer->nextPendingConnection();  
QObject::connect(clientConnection, &QTcpSocket::readyRead, this, &MainWindow::readMessage); 

（5）发数据

// 用于暂存要发送的数据  
    QByteArray block;  
    QDataStream out(&block, QIODevice::WriteOnly);  
  
    // 设置数据流的版本，客户端和服务器端使用的版本要相同  
    out.setVersion(QDataStream::Qt_5_6);  
    out << (quint16)0;  
    out << tr("connect sucessful !");  
    out.device()->seek(0);  
    out << (quint16)(block.size() - sizeof(quint16));  
  
    clientConnection->write(block);  
    clientConnection->flush(); 

（6）读数据

QDataStream in(clientConnection);  
  
    // 设置数据流版本，这里要和服务器端相同  
    in.setVersion(QDataStream::Qt_5_6);  
  
    in >> blockSize;  
    in >> message;  

3、客户端

（1）创建QTcpSocket套接字对象

tcpSocket = new QTcpSocket(this);  

（2）使用这个对象连接服务器

server->listen(QHostAddress::Any, port)  

（3）当服务器被客户端访问时，会发出newConnection()信号，因此为该信号添加槽函数，并用一个QTcpSocket对象接受客户端访问

connect(server,&QTcpServer::newConnection,this,&MainWindow::server_New_Connect);  
  
void MainWindow::server_New_Connect()  
{  
    //获取客户端连接  
    socket = server->nextPendingConnection();  
}  

代码：

客户端

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
#include <QAbstractSocket>
class QTcpSocket;
 
namespace Ui {
class MainWindow;
}
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
private:
    QList<QString> DataList;
    Ui::MainWindow *ui;
    QTcpSocket *tcpSocket;
    QString message;
    // 用来存放数据的大小信息
    quint16 blockSize;
 
private slots:
    void newConnect();
    void readMessage();
    void displayError(QAbstractSocket::SocketError);
 
    void on_ConPushButton_clicked();
    void on_SendPushButton_clicked();
    void on_disConPushButton_clicked();
    void on_SeeDatabtn_clicked();
    void on_ClearBtn_clicked();
};
 
#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtNetwork>
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ui->hostLineEdit->setText("127.0.0.1");
    ui->portLineEdit->setText("30000");
    tcpSocket = new QTcpSocket(this);
 
    connect(tcpSocket, &QTcpSocket::readyRead, this, &MainWindow::readMessage);
    connect(tcpSocket, SIGNAL(error(QAbstractSocket::SocketError)),
            this, SLOT(displayError(QAbstractSocket::SocketError)));
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::newConnect(){
    // 初始化数据大小信息为0
    blockSize = 0;
 
    // 取消已有的连接
    tcpSocket->abort();
    tcpSocket->connectToHost(ui->hostLineEdit->text(),
                             ui->portLineEdit->text().toInt());
    ui->conn_state->setText("已连接");
}
 
void MainWindow::readMessage(){
    QDataStream in(tcpSocket);
 
    // 设置数据流版本，这里要和服务器端相同
    in.setVersion(QDataStream::Qt_5_6);
 
 
    in >> blockSize;
    // 将接收到的数据存放到变量中
    in >> message;
    // 显示接收到的数据
    ui->MessageAccept->setText(message);
    if(message != "connect sucessful !"){
        DataList.append(message);
    }
}
 
 
 
void MainWindow::displayError(QAbstractSocket::SocketError)
{
    qDebug() << tcpSocket->errorString();
    ui->conn_state->setText("连接发生错误！请重新连接。");
}
 
void MainWindow::on_ConPushButton_clicked()
{
    newConnect();
}
 
void MainWindow::on_SendPushButton_clicked()
{
    // 用于暂存要发送的数据
    QByteArray block;
    QDataStream out(&block, QIODevice::WriteOnly);
 
    // 设置数据流的版本，客户端和服务器端使用的版本要相同
    out.setVersion(QDataStream::Qt_5_6);
    out << (quint16)0;
    out << ui->MesslineEdit->text();
    out.device()->seek(0);
    out << (quint16)(block.size() - sizeof(quint16));
 
    tcpSocket->write(block);
    tcpSocket->flush();
}
 
void MainWindow::on_disConPushButton_clicked()
{
    tcpSocket->disconnectFromHost();
    ui->conn_state->setText("未连接");
}
 
//查看接收数据
void MainWindow::on_SeeDatabtn_clicked()
{
    for(int i=0;i<DataList.size();i++){
        qDebug() << DataList.at(i);
    }
}
 
//清空接收数据
void MainWindow::on_ClearBtn_clicked()
{
    DataList.clear();
}

服务器端

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
 
#include <QMainWindow>
#include <QtNetwork>
class QTcpServer;
 
namespace Ui {
class MainWindow;
}
 
class MainWindow : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
 
private:
    Ui::MainWindow *ui;
    QTcpServer *tcpServer;
    QTcpSocket *clientConnection;
    QString message;
    // 用来存放数据的大小信息
    quint16 blockSize;
    QTimer *timer;
 
private slots:
    //void acceptMessage();
    void sendMessage();
    void readMessage();
 
    void displayError(QAbstractSocket::SocketError);
    void on_send_clicked();
 
    void timerSendMess();
};
 
#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtNetwork>
#include <QTime>
#include <QTimer>
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
 
    tcpServer = new QTcpServer(this);
    if((!tcpServer->listen(QHostAddress::LocalHost, 30000))){
        qDebug() << tcpServer->errorString();
        close();
    }
    connect(tcpServer, &QTcpServer::newConnection,
            this, &MainWindow::sendMessage);
 
    //定时器
    timer = new QTimer(this);
    connect(timer,&QTimer::timeout,this,&MainWindow::timerSendMess);
 
}
 
MainWindow::~MainWindow()
{
    clientConnection->close();
    delete ui;
}
 
//定时发送数据
void MainWindow::timerSendMess(){
    int rand = qrand() % 30000;
    ui->MessSend->setText(QString::number(rand, 10));
 
    // 用于暂存要发送的数据
    QByteArray block;
    QDataStream out(&block, QIODevice::WriteOnly);
 
    // 设置数据流的版本，客户端和服务器端使用的版本要相同
    out.setVersion(QDataStream::Qt_5_6);
    out << (quint16)0;
    out << QString::number(rand, 10);
    out.device()->seek(0);
    out << (quint16)(block.size() - sizeof(quint16));
 
    clientConnection->write(block);
    clientConnection->flush();
}
 
void MainWindow::sendMessage(){
 
    // 获取已经建立的连接的套接字
    clientConnection = tcpServer->nextPendingConnection();
    QObject::connect(clientConnection, &QTcpSocket::readyRead, this, &MainWindow::readMessage);
    connect(clientConnection, SIGNAL(error(QAbstractSocket::SocketError)),
            this, SLOT(displayError(QAbstractSocket::SocketError)));
 
    // 用于暂存要发送的数据
    QByteArray block;
    QDataStream out(&block, QIODevice::WriteOnly);
 
    // 设置数据流的版本，客户端和服务器端使用的版本要相同
    out.setVersion(QDataStream::Qt_5_6);
    out << (quint16)0;
    out << tr("connect sucessful !");
    out.device()->seek(0);
    out << (quint16)(block.size() - sizeof(quint16));
 
    clientConnection->write(block);
    clientConnection->flush();
 
    ui->waitconn->setText(tr("连接成功！"));
}
 
void MainWindow::on_send_clicked()
{
    // 用于暂存要发送的数据
    QByteArray block;
    QDataStream out(&block, QIODevice::WriteOnly);
 
    // 设置数据流的版本，客户端和服务器端使用的版本要相同
    out.setVersion(QDataStream::Qt_5_6);
    out << (quint16)0;
    out << ui->MessSend->text();
    out.device()->seek(0);
    out << (quint16)(block.size() - sizeof(quint16));
 
    clientConnection->write(block);
    clientConnection->flush();
}
 
void MainWindow::readMessage(){
    QDataStream in(clientConnection);
 
    // 设置数据流版本，这里要和服务器端相同
    in.setVersion(QDataStream::Qt_5_6);
 
    in >> blockSize;
    in >> message;
 
    //读出内容和大小
    qDebug() << blockSize;
    qDebug() << message;
 
    if(message=="ACTION"){
        //1s一个数据
        timer->start(300);
    }
    if(message=="STOP"){
        timer->stop();
    }
 
    ui->MessAccept->setText(message);
}
 
void MainWindow::displayError(QAbstractSocket::SocketError){
    qDebug() << clientConnection->errorString();
    ui->waitconn->setText("未连接，等待连接");
}