转自：https://blog.csdn.net/m0_37290785/article/details/78720883

waitForConnected() 等待链接的建立

waitForReadyRead() 等待新数据的到来
waitForBytesWritten() 等待数据写入socket
waitForDisconnected() 等待链接断开

开始前在项目.pro里面添加如下：

       QT += core gui network

=========server==============

#include "testnet.h"
#include "ui_testnet.h"
#include <QtGui>
Testnet::Testnet(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::Testnet)
{
    ui->setupUi(this);
 
 
    this->connect(ui->pushButton_start,SIGNAL(clicked()),this,SLOT(startTcpserver()));
    this->connect(ui->pushButton_send,SIGNAL(clicked()),this,SLOT(sendMessage()));
}
 
Testnet::~Testnet()
{
    delete ui;
}
 
void Testnet::startTcpserver()
{
    m_tcpServer = new QTcpServer(this);
 
    m_tcpServer->listen(QHostAddress::Any,19999); //监听任何连上19999端口的ip
 
    connect(m_tcpServer,SIGNAL(newConnection()),this,SLOT(newConnect())); //新连接信号触发，调用newConnect()槽函数，这个跟信号函数一样，其实你可以随便取。
}
 
void Testnet::newConnect()
{
        m_tcpSocket = m_tcpServer->nextPendingConnection(); //得到每个连进来的socket
        connect(m_tcpSocket,SIGNAL(readyRead()),this,SLOT(readMessage())); //有可读的信息，触发读函数槽
 
}
 
void Testnet::readMessage()    //读取信息
{
//    ui->textEdit_rec->te
    QByteArray qba= m_tcpSocket->readAll(); //读取
    qDebug()<<qba;
    QString ss=QVariant(qba).toString();
    ui->textEdit_rec->setText(ss);
 
}
 
void Testnet::sendMessage() //发送信息
{
    QString strMesg= ui->lineEdit_sendmessage->text();
    qDebug()<<strMesg;
    m_tcpSocket->write(strMesg.toStdString().c_str(),strlen(strMesg.toStdString().c_str())); //发送
}

=======client========

#include "testnet_c.h"
#include "ui_testnet_c.h"
 
 
 
testnet_c::testnet_c(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::testnet_c)
{
    ui->setupUi(this);
 
    this->connect(ui->pushButton_con,SIGNAL(clicked()),this,SLOT(connectServer()));
    this->connect(ui->pushButton_send,SIGNAL(clicked()),this,SLOT(sendMesg()));
}
 
testnet_c::~testnet_c()
{
    delete ui;
}
 
 
void testnet_c::connectServer()
{
    m_tcpSocket = new QTcpSocket(this);
    m_tcpSocket->abort();
    m_tcpSocket->connectToHost("192.168.1.178",19999);
 
    connect(m_tcpSocket,SIGNAL(readyRead()),this,SLOT(readMesg()));
}
 
void testnet_c::readMesg() //读取信息
{
   QByteArray qba =   m_tcpSocket->readAll();
 
   ui->textEdit_recmesg->clear();
 
   qDebug()<<qba;
   QString ss=QVariant(qba).toString();
   ui->textEdit_recmesg->setText(ss);
}
 
void testnet_c::sendMesg() //发送信息
{
    QString ss= ui->lineEdit_sendmesg->text();
    m_tcpSocket->write(ss.toStdString().c_str(),strlen(ss.toStdString().c_str()));
    ui->lineEdit_sendmesg->clear();
}