TCP

项目文件需要添加network模块，之后最好编译不运行一下（锤子）

TCP通信流程：

客户窗口

#include "clientwidget.h"
#include "ui_clientwidget.h"
#include <QHostAddress>

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

    tcpSocket = NULL;

    //分配空间，指定父对象
    tcpSocket = new QTcpSocket(this);

    setWindowTitle("客户端");


    connect(tcpSocket, &QTcpSocket::connected,
            [=]()
            {
                ui->textEditRead->setText("成功和服务器建立好连接");
            }
            );

    connect(tcpSocket, &QTcpSocket::readyRead,
            [=]()
            {
                //获取对方发送的内容
                QByteArray array = tcpSocket->readAll();
                //追加到编辑区中
                ui->textEditRead->append(array);
            }

            );

}

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

void ClientWidget::on_buttonConnect_clicked()
{
    //获取服务器ip和端口
    QString ip = ui->lineEditIP->text();
    qint16 port = ui->lineEditPort->text().toInt();

    //主动和服务器建立连接
    tcpSocket->connectToHost(QHostAddress(ip), port);

}

void ClientWidget::on_buttonSend_clicked()
{
    //获取编辑框内容
    QString str = ui->textEditWrite->toPlainText();
    //发送数据
    tcpSocket->write( str.toUtf8().data() );

}

void ClientWidget::on_buttonClose_clicked()
{
    //主动和对方断开连接
    tcpSocket->disconnectFromHost();
    tcpSocket->close();
}

服务器

#include "serverwidget.h"
#include "ui_serverwidget.h"

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

    tcpServer = NULL;
    tcpSocket = NULL;

    //监听套接字，指定父对象，让其自动回收空间
    tcpServer = new QTcpServer(this);

    tcpServer->listen(QHostAddress::Any, 8888);

    setWindowTitle("服务器: 8888");

    connect(tcpServer, &QTcpServer::newConnection,
            [=]()
            {
                //取出建立好连接的套接字
                tcpSocket = tcpServer->nextPendingConnection();

                //获取对方的IP和端口
                QString ip = tcpSocket->peerAddress().toString();
                qint16 port = tcpSocket->peerPort();
                QString temp = QString("[%1:%2]:成功连接").arg(ip).arg(port);

                ui->textEditRead->setText(temp);

                connect(tcpSocket, &QTcpSocket::readyRead,
                        [=]()
                        {
                            //从通信套接字中取出内容
                            QByteArray array = tcpSocket->readAll();
                            ui->textEditRead->append(array);
                        }

                        );


            }

            );

}

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

void ServerWidget::on_buttonSend_clicked()
{
    if(NULL == tcpSocket)
    {
        return;
    }
    //获取编辑区内容
    QString str = ui->textEditWrite->toPlainText();
    //给对方发送数据， 使用套接字是tcpSocket
    tcpSocket->write( str.toUtf8().data() );

}

void ServerWidget::on_buttonClose_clicked()
{
    if(NULL == tcpSocket)
    {
        return;
    }

    //主动和客户端端口连接
    tcpSocket->disconnectFromHost();
    tcpSocket->close();
    tcpSocket = NULL;
}