QT之TCP通信简单实现

一、服务器端实现

1.tcpserver.h

#ifndef TCPSERVER_H
#define TCPSERVER_H

#include <QMainWindow>
#include <QtNetWork>

namespace Ui {
class TcpServer;
}

class TcpServer : public QMainWindow
{
    Q_OBJECT

public:
    explicit TcpServer(QWidget *parent = 0);
    ~TcpServer();

private:
    Ui::TcpServer *ui;
    QTcpServer *tcpServer;

private slots:
    void sendMessage();
};

#endif // TCPSERVER_H

2.tcpserver.cpp

#include "tcpserver.h"
#include "ui_tcpserver.h"

TcpServer::TcpServer(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::TcpServer)
{
    ui->setupUi(this);
    tcpServer = new QTcpServer(this);
    if(!tcpServer->listen(QHostAddress::LocalHost,6666))
    {
        qDebug()<<tcpServer->errorString();
        close();
    }
    connect(tcpServer,SIGNAL(newConnection()),this,SLOT(sendMessage()));  //连接信号和相应槽函数
                                                                        //有新的连接进来就执行sendMessage函数
}

TcpServer::~TcpServer()
{
    delete ui;
    delete tcpServer;
}


void TcpServer::sendMessage()
{
    QByteArray block;      //用于暂存要发的数据
    QDataStream out(&block,QIODevice::WriteOnly);   //使用数据流写入数据
    out.setVersion(QDataStream::Qt_5_6);  //设置数据流的版本，客户端和服务器端使用版本要相同
    out<<(quint16) 0;
    out<<tr("Hello Tcp!!!");
    out.device()->seek(0);
    out<<(quint16) (block.size()-sizeof(quint16));
    QTcpSocket *clientConnection=tcpServer->nextPendingConnection();  //获取已经建立的连接的子套接字
    connect(clientConnection,SIGNAL(disconnected()),clientConnection,SLOT(deleteLater()));
    clientConnection->write(block);
    clientConnection->disconnectFromHost();
    ui->statusLabel->setText("Send message successful!!!");
}

二、客户端实现

1.tcpclient.h

#ifndef TCPCLIENT_H
#define TCPCLIENT_H

#include <QMainWindow>
#include <QtNetwork>

namespace Ui {
class TcpClient;
}

class TcpClient : public QMainWindow
{
    Q_OBJECT

public:
    explicit TcpClient(QWidget *parent = 0);
    ~TcpClient();

private:
    Ui::TcpClient *ui;
    QTcpSocket *tcpClient;
    QString message;                 //存放从服务器接收到的字符串
    quint16 blockSize;               //存放文件的大小信息

private slots:
    void newConnect();               //连接服务器
    void readMessage();              //接收数据
    void displayError(QAbstractSocket::SocketError);   //显示错误
    void on_pushButton_clicked();
};

#endif // TCPCLIENT_H

2.tcpclient.cpp

#include "tcpclient.h"
#include "ui_tcpclient.h"

TcpClient::TcpClient(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::TcpClient)
{
    ui->setupUi(this);
    tcpClient=new QTcpSocket(this);
    connect(tcpClient,SIGNAL(readyRead()),this,SLOT(readMessage()));  //有数据来时执行readMessage函数
    connect(tcpClient,SIGNAL(error(QAbstractSocket::SocketError)),
            this,SLOT(displayError(QAbstractSocket::SocketError)));   //发生错误时执行displayError函数
}

TcpClient::~TcpClient()
{
    delete ui;
    delete tcpClient;
}


void TcpClient::newConnect()
{
    blockSize=0;
    tcpClient->abort();   //取消已经有的连接
    tcpClient->connectToHost(ui->hostLineEdit->text(),
                             ui->portLineEdit->text().toInt());
}


void TcpClient::readMessage()
{
    QDataStream in(tcpClient);
    in.setVersion(QDataStream::Qt_5_6);   //设置数据流版本，这里要和服务器端相同
    if(blockSize==0)
    {
        if(tcpClient->bytesAvailable()<(int)sizeof(quint16)) return;
        in>>blockSize;
    }
    if(tcpClient->bytesAvailable()<blockSize) return;
    in>>message;
    ui->messageLabel->setText(message);
}


void TcpClient::displayError(QAbstractSocket::SocketError)
{
    qDebug()<<tcpClient->errorString();   //输出出错信息
}




void TcpClient::on_pushButton_clicked()
{
    newConnect();  //请求连接
}

三、运行结果