#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include "myserver.h"

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

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

    Ui::MainWindow *ui;

public slots:
    void on_dataInTextEdit();

private slots:
    void on_pushButton_start_clicked();

    void on_pushButton_stop_clicked();

private:
    Myserver server;
    Myserver server1;
};

#endif // MAINWINDOW_H

#ifndef MYSERVER_H
#define MYSERVER_H

#include <QTcpServer>
#include <QTcpSocket>

class Myserver : public QTcpServer
{
    Q_OBJECT
public:
    Myserver ();

    QTcpSocket *socket;
    QByteArray data;

public slots:
    void incomingConnection(qintptr socketDescriptor);
    void sockReady();
    void sockDisc();
};

#endif // MYSERVER_H

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}

.......

void MainWindow::on_dataInTextEdit()
{
    ui->lineEdit->setText("text");
    qDebug()<<"on_dataInTextEdit";
}

#include "myserver.h"
#include "ui_mainwindow.h"
#include "mainwindow.h"

Myserver::Myserver()
{
}

void Myserver::incomingConnection(qintptr socketDescriptor)
{
    socket = new QTcpSocket(this);
    socket->setSocketDescriptor(socketDescriptor);
    connect(socket,SIGNAL(readyRead()),this,SLOT(sockReady()));
}

.......

void Myserver::sockReady()
{
    qDebug()<<"Socket is ready";
    data = socket->readAll();
    qDebug()<<"Data: "<<data<<"from"<<serverPort();
    MainWindow *mw = new MainWindow();
    mw->on_dataInTextEdit();
}