Qt的Socket数据通讯的一个例子。

QTcpServer类 用来侦听端口 ，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 当前连接只需要 调用 qtcpsocket::close();就关闭了当前连接

下面有两个例子

   服务器端

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 返回到客户端。然后close断开连接

客户端

  用的书图形界面，一个输入框 输入数据 然后发送，最后 QMessagebox显示服务器返回消息

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服务器端(三个文件)

#ifndef MYSERVER_H#define MYSERVER_H#include<QTcpSocket>#include<iostream>#include <QObject>#include<QTcpServer>class myserver : public QTcpServer{    Q_OBJECTpublic:    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");//返回给客户端    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();}

客户端（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_OBJECTpublic:    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();}
运行截图：

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