原文：https://blog.csdn.net/uyy203/article/details/54960276

在Qt上建立Tcp server 和 client 间的简易通讯，实现效果如下

image.png

首先要记得在工程目录中的pro文件中 加入 ，这样才能开启网络服务

QT += network

//mainwindow.h

#include "tcpserverwindow.h"
#include "ui_tcpserverwindow.h"
 
TcpServerWindow::TcpServerWindow(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::TcpServerWindow)
{
    ui->setupUi(this);
 
    tcpSocket=new QTcpSocket(this);
    tcpServer=new QTcpServer(this);
 
    setListener();
 
     /**信号与槽**/
 
    //newConnection()用于当有客户端访问时发出信号，acceptConnection()信号处理函数
    connect(tcpServer,SIGNAL(newConnection()),this,SLOT(acceptConnection()));
 
    //当tcpSocket在接受客户端连接时出现错误时，displayError(QAbstractSocket::SocketError)进行错误提醒并关闭tcpSocket。
    connect(tcpSocket,SIGNAL(error(QAbstractSocket::SocketError)),SLOT(displayError(QAbstractSocket::SocketError)));
 
}
 
 
    //监听是否有客户端来访，且对任何来访者监听，端口为6666
void TcpServerWindow::setListener(){
    if(!tcpServer->listen(QHostAddress::Any,6666)){
         qDebug()<<tcpServer->errorString();
        close();
    }else {
        qDebug()<<"listening";
    }
 
}
 
 
void TcpServerWindow::displayError(QAbstractSocket::SocketError)
 
{
 
   qDebug()<<tcpSocket->errorString();
 
   tcpSocket->close();
 
}
 
 
void TcpServerWindow::acceptConnection(){
    tcpSocket=tcpServer->nextPendingConnection();
}
 
 
 
TcpServerWindow::~TcpServerWindow()
{
    delete ui;
}
 
//点击发送按钮发送消息
void TcpServerWindow::on_SendBtn_clicked()
{
    //以utf-8字符集格式发送，支持中文
    tcpSocket->write(ui->SendText->text().toUtf8());
 
    //以拉丁字符集格式发送
//    tcpSocket->write(ui->SendText->text().toLatin1());
}

//mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
 
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
 
    tcpServerWindow=new TcpServerWindow;
    tcpClientWindow=new TcpClientWindow;
 
 
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::on_server_clicked()
{
    tcpServerWindow->show();
 
}
 
void MainWindow::on_client_clicked()
{
    tcpClientWindow->show();
}

*************Client***************

//tcpclientwindow.h

#ifndef TCPCLIENTWINDOW_H
#define TCPCLIENTWINDOW_H
 
#include<QtNetwork/QTcpSocket>
#include<QtNetwork>
#include <QDialog>
 
namespace Ui {
class TcpClientWindow;
}
 
class TcpClientWindow : public QDialog
{
    Q_OBJECT
 
public:
    explicit TcpClientWindow(QWidget *parent = 0);
    ~TcpClientWindow();
 
private:
    Ui::TcpClientWindow *ui;
 
    QTcpSocket *tcpSocket;
 
    void newTcpConnection();
 
private slots:
    void displayError(QAbstractSocket::SocketError);
    void revData();
};
 
#endif // TCPCLIENTWINDOW_H

//tcpclientwindow.cpp

#include "tcpclientwindow.h"
#include "ui_tcpclientwindow.h"
 
TcpClientWindow::TcpClientWindow(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::TcpClientWindow)
{
    ui->setupUi(this);
 
    tcpSocket=new QTcpSocket(this);
 
    newTcpConnection();
 
    /**信号与槽**/
 
    //readyRead()表示服务端发送数据过来即发动信号，接着revData()进行处理。
    connect(tcpSocket,SIGNAL(readyRead()),this,SLOT(revData()));
 
    connect(tcpSocket,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(displayError(QAbstractSocket::SocketError)));
 
 
}
 
    //接收字符串
void TcpClientWindow::revData(){
    QString data=tcpSocket->readAll();
    ui->ReceiveText->setText(data);
}
 
//新建连接
void TcpClientWindow::newTcpConnection(){
    tcpSocket->abort();
    tcpSocket->connectToHost("127.0.0.1",6666);
 
    }
 
void TcpClientWindow::displayError(QAbstractSocket::SocketError){
    qDebug()<<tcpSocket->errorString();
    tcpSocket->close();
}
 
 
TcpClientWindow::~TcpClientWindow()
{
    delete ui;
}

***************Server***************

//tcpserverwindow.h

#ifndef TCPSERVERWINDOW_H
#define TCPSERVERWINDOW_H
 
#include<QtNetwork/QTcpSocket>
#include<QtNetwork/QTcpServer>
#include <QDialog>
 
namespace Ui {
class TcpServerWindow;
}
 
class TcpServerWindow : public QDialog
{
    Q_OBJECT
 
public:
    explicit TcpServerWindow(QWidget *parent = 0);
    ~TcpServerWindow();
 
private:
    Ui::TcpServerWindow *ui;
 
    QTcpSocket *tcpSocket;
    QTcpServer *tcpServer;
 
    void setListener();
 
 
private slots:
 
    void acceptConnection();
 
    void displayError(QAbstractSocket::SocketError);
 
    void on_SendBtn_clicked();
};
 
#endif // TCPSERVERWINDOW_H

//tcpserverwindow.cpp

#include "tcpserverwindow.h"
#include "ui_tcpserverwindow.h"
 
TcpServerWindow::TcpServerWindow(QWidget *parent) :
    QDialog(parent),
    ui(new Ui::TcpServerWindow)
{
    ui->setupUi(this);
 
    tcpSocket=new QTcpSocket(this);
    tcpServer=new QTcpServer(this);
 
    setListener();
 
     /**信号与槽**/
 
    //newConnection()用于当有客户端访问时发出信号，acceptConnection()信号处理函数
    connect(tcpServer,SIGNAL(newConnection()),this,SLOT(acceptConnection()));
 
    //当tcpSocket在接受客户端连接时出现错误时，displayError(QAbstractSocket::SocketError)进行错误提醒并关闭tcpSocket。
    connect(tcpSocket,SIGNAL(error(QAbstractSocket::SocketError)),SLOT(displayError(QAbstractSocket::SocketError)));
 
}
 
 
    //监听是否有客户端来访，且对任何来访者监听，端口为6666
void TcpServerWindow::setListener(){
    if(!tcpServer->listen(QHostAddress::Any,6666)){
         qDebug()<<tcpServer->errorString();
        close();
    }else {
        qDebug()<<"listening";
    }
 
}
 
 
void TcpServerWindow::displayError(QAbstractSocket::SocketError)
 
{
 
   qDebug()<<tcpSocket->errorString();
 
   tcpSocket->close();
 
}
 
 
void TcpServerWindow::acceptConnection(){
    tcpSocket=tcpServer->nextPendingConnection();
}
 
 
 
TcpServerWindow::~TcpServerWindow()
{
    delete ui;
}
 
//点击发送按钮发送消息
void TcpServerWindow::on_SendBtn_clicked()
{
    //以utf-8字符集格式发送，支持中文
    tcpSocket->write(ui->SendText->text().toUtf8());
 
    //以拉丁字符集格式发送
//    tcpSocket->write(ui->SendText->text().toLatin1());
}