Qt-tcp连接

服务端：

1.创建用于监听套接字

2.设置套接字为监听

3.当有新的客户端要连接时，该套接字会发出newConnection()的信号，

4.接着要建立连接时调用nextPendingConnect（）返回一个QTcpSocket对象用于通信

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include<QTcpServer>
#include<QTcpSocket>
#include<QDebug>
#include<QHostAddress>
namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

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

private:
    Ui::Widget *ui;
    QTcpServer *my_sever;
    QList<QTcpSocket* > my_client;
    int len;
private slots:
    void newConnectionSlots();//新用户连接
    void disConnectSlots();//客户端断开
    void readyReadSlots();
    //客户端读取消息


    void on_pushButton_listen_clicked();
    void on_pushButton_send_clicked();
};

#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"
#include<QMessageBox>
#include<QDataStream>
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    this->setWindowTitle("服务端");
    len=0;
    ui->lcdNumber_sockeNum->display(len);
    my_sever=new QTcpServer();
    connect(my_sever,&QTcpServer::newConnection,this,&Widget::newConnectionSlots);

}

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

void Widget::newConnectionSlots()
{
    QTcpSocket *sock=my_sever->nextPendingConnection();
    my_client.append(sock);
    len++;
    ui->lcdNumber_sockeNum->display(len);
    QString info;
    info+="ip="+sock->peerAddress().toString()+" 端口="+QString::number(sock->peerPort());
    ui->textBrowser_clientInfo->append(info);
    connect(sock,&QTcpSocket::readyRead,this,&Widget::readyReadSlots);
}

void Widget::disConnectSlots()
{

}

void Widget::readyReadSlots()
{
    QTcpSocket *sock=qobject_cast<QTcpSocket*>(sender());
    if(sock!=NULL)
    {
        if(sock->isReadable())
        {
            int len=sock->bytesAvailable();
            QByteArray arr=sock->read(len>65536?65536:len);
            QString str=QString::fromLocal8Bit(arr);
            qDebug()<<str<<endl;
            ui->textBrowser_recv->append(str);
        }
    }


}





void Widget::on_pushButton_listen_clicked()
{
    QString ip=ui->lineEdit_address->text();
    qint16 port=ui->lineEdit_port->text().toInt();
    QHostAddress address=QHostAddress(ip);
    qDebug()<<ip<<" "<<port<<endl;
    if(!my_sever->isListening())
    {
        if(!my_sever->listen(address,port))
        {
            qDebug()<<my_sever->errorString();
            return ;
        }
        else
        {
            ui->pushButton_listen->setText("停止监听");
        }
    }
    else
    {
        my_sever->close();
        ui->pushButton_listen->setText("开始监听");
    }
}

void Widget::on_pushButton_send_clicked()
{

    QString str=ui->plainTextEdit_sendInfo->toPlainText();
    if(str=="")
    {
        QMessageBox::warning(this,"警告","发送内容不能为空");
        return ;
    }
    QString res;
    res+="服务端: "+str;
     QByteArray arr=res.toUtf8();
    ui->plainTextEdit_sendInfo->clear();
    ui->plainTextEdit_sendInfo->setFocus();
    for(int i=0;i<my_client.size();i++)
    {
        my_client[i]->write(arr);
    }

    ui->textBrowser_recv->append(res);

}

客户端：

1.创建套接字

2.连接服务器 connectToHost();

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include<QTcpServer>
#include<QTcpSocket>
namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();
private slots:
    void readyReadSlots();

    void on_pushButton_send_clicked();

    void on_pushButton_listen_clicked();

private:
    Ui::Widget *ui;
    QTcpSocket *my_socket;
    bool connectstat;

};

#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"
#include<QHostAddress>
#include<QDebug>
#include<QMessageBox>
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    this->setWindowTitle("客户端");
    my_socket=new QTcpSocket();
    connectstat=false;
    connect(my_socket,&QTcpSocket::readyRead,this,&Widget::readyReadSlots);
}

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

void Widget::readyReadSlots()
{
    int len=my_socket->bytesAvailable();
    QByteArray arr=my_socket->read(len>65536?65536:len);
    QString str=QString::fromUtf8(arr);
    ui->textBrowser_recv->append(str);

}



void Widget::on_pushButton_send_clicked()
{
    QString str=ui->plainTextEdit_sendInfo->toPlainText();
    if(str=="")
    {
        QMessageBox::warning(this,"警告","发送的内容不能为空");
        return ;
    }
    ui->plainTextEdit_sendInfo->clear();
    ui->plainTextEdit_sendInfo->setFocus();
    QString res;
    res+="ip="+my_socket->peerAddress().toString()+" 端口="+QString::number(my_socket->peerPort())+": "+str;
    QByteArray arr=res.toLocal8Bit();
    my_socket->write(arr);
    ui->textBrowser_recv->append(res);
}

void Widget::on_pushButton_listen_clicked()
{
    QString ip=ui->lineEdit_address->text();
    qint16 port=ui->lineEdit_port->text().toInt();
    QHostAddress address=QHostAddress(ip);
    if(!connectstat)//如果没有连接
    {
        my_socket->connectToHost(address,port);
        if(!my_socket->waitForConnected(5000))
        {
            qDebug()<<my_socket->errorString();
            return ;
        }
        else
        {
            ui->pushButton_listen->setText("断开连接");
            connectstat=true;
        }
    }
    else
    {
        ui->pushButton_listen->setText("开始监听");
        connectstat=false;
    }
}

成果：