Qt的Socket数据通讯的一个样例。

QTcpServer类 用来侦听port ，获取QTcpSocket.

QTcpSocket有  connected的信号（已经连接）,还有readyread()信号，表示已经有数据发过来了。准备读取。

  若要关闭 当前连接仅仅须要 调用 qtcpsocket::close();就关闭了当前连接

以下有两个样例

   server端

用的是控制台程序（QT） 当用户 发送数据过来 就cout显示。然后就write一个 I Love You的字符串 返回到client。然后close断开连接

client

  用的书图形界面。一个输入框 输入数据 然后发送，最后 QMessagebox显示server返回消息

=======================

server端(三个文件)

#ifndef MYSERVER_H
#define MYSERVER_H
#include<QTcpSocket>
#include<iostream>
#include <QObject>
#include<QTcpServer>
class myserver : public QTcpServer
{
    Q_OBJECT
public:
    QTcpSocket * socket;
    QTcpServer *server;
    myserver();
private slots:
    void getData();
    void newconnectslot();
};
#endif // MYSERVER_H


#include "myserver.h"
#include<QByteArray>
#include<QString>
#include<QDataStream>
myserver::myserver()
{
    this->socket=new QTcpSocket;
    this->server=new QTcpServer;


    if(this->server->listen(QHostAddress::Any,520))
    {
        std::cout<<"bind port 520 successful."<<std::endl;
    }else
    {
        std::cout<<"bind port 520 failed."<<std::endl;
    }
     QObject::connect(this->server,SIGNAL(newConnection()),this,SLOT(newconnectslot()));


}


void myserver::newconnectslot()
{
    this->socket=this->server->nextPendingConnection();
    connect(this->socket,SIGNAL(readyRead()),this,SLOT(getData()));


}
void myserver::getData()
{
    QByteArray by=this->socket->readAll();
    QDataStream ds(by);
    QString x;
    ds>>x;
    QByteArray ba = x.toLatin1();


    char * p=ba.data();
    std::cout<<p<<std::endl;
    socket->write("I love you");//返回给client
    this->socket->close();//断开连接
}


#include <QCoreApplication>
#include<iostream>
#include"myserver.h"
#include<QHostAddress>
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    std::cout<<"--Server initialized By HanHan--"<<std::endl;
    myserver *server=new myserver;
    return a.exec();
}

client（三个文件）

#ifndef MAINWINDOW_H
#define MAINWINDOW_H


#include <QMainWindow>
#include<QString>
#include<QByteArray>
#include<QDataStream>


#include<QTcpSocket>
namespace Ui {
class MainWindow;
}


class MainWindow : public QMainWindow
{
    Q_OBJECT


public:
    QTcpSocket * socket;
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();


private slots:
    void connnectslot();
    void on_btn_send_clicked();
    void readyslot();


private:
    Ui::MainWindow *ui;
};


#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include<QHostAddress>
#include<QMessageBox>
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    this->socket=new QTcpSocket;
}


MainWindow::~MainWindow()
{
    delete ui;
}


void MainWindow::on_btn_send_clicked()
{


    QHostAddress address("127.0.0.1");
    this->socket->connectToHost(address,520);
    connect(this->socket,SIGNAL(connected()),this,SLOT(connnectslot()));
    connect(this->socket,SIGNAL(readyRead()),this,SLOT(readyslot()));//接收发来的数据
}
void MainWindow::connnectslot()
{
     QString data=this->ui->data_edit->toPlainText();
     QByteArray array;
     QDataStream ds(&array,QIODevice::WriteOnly);
     ds<<data;
     this->socket->write(array);


}

void MainWindow::readyslot()
{
    QString x=this->socket->readAll();
    QMessageBox::about(this,"x",x);


}
#include "mainwindow.h"
#include <QApplicatio>


int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();


    return a.exec();
}




执行截图：

n