Qt实现TcpClient和TcpServer连接收发数据

Qt实现TcpClient和TcpServer连接收发数据，TcpClent实现上位机给串口发送指令，没有什么问题了，可是让下位机做出相应的指令。

首先在TcpClient和TcpServer中的pro加入QT+=network。

界面设计：





接受指令设计：

tcpclient.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QWidget>
#include <QMainWindow>
#include <QDialog>
#include <QAbstractSocket>
class QTcpSocket;
namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
Q_OBJECT

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

private:
Ui::MainWindow *ui;
QTcpSocket *tcpSocket;
QString currentForture;
quint16 blockSize;
private slots:
void newConnect();
void readMessage();
void displayError(QAbstractSocket::SocketError);

//void on_connectButton_clicked();
void on_connectpushButton_clicked();
};

#endif // MAINWINDOW_H

tcpclient.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtNetwork>
#include <QTimer>
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
tcpSocket=new QTcpSocket();
connect(tcpSocket,SIGNAL(readyRead()),this,SLOT(readMessage()));
connect(tcpSocket,SIGNAL(error(QAbstractSocket::SocketError)),this,SLOT(displayError(QAbstractSocket::SocketError)));

}

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

void MainWindow::newConnect()
{
//初始化数据大小信息为0
blockSize=0;
//取消已有的连接
tcpSocket->abort();
//tcpSocket->connectToHost(ui->hostlineEdit->text(),ui->portlineEdit_2->text().toInt());
tcpSocket->connectToHost(QHostAddress::LocalHost,4196);
}

void MainWindow::readMessage()
{
QByteArray block;
QDataStream in(tcpSocket);
//QDataStream out(&block,QIODevice::ReadWrite);
//设置数据流版本
in.setVersion(QDataStream::Qt_5_6);
//out.setVersion(QDataStream::Qt_5_6);

//如果是刚开始接受数据
if(blockSize==0)
{
if(tcpSocket->bytesAvailable()<(int)sizeof(quint16))
{
//将接收到的数据存放在变量中
in>>blockSize;
}
if(tcpSocket->bytesAvailable()<blockSize)
return;
QString nextFortune;
in>>nextFortune;
if(nextFortune==currentForture)
{
QTimer::singleShot(0,this,&MainWindow::newConnect);
return;
}
currentForture=nextFortune;

//显示接收到的数据
qDebug()<<currentForture;
ui->messagelabel->setText(currentForture);
}

}

void MainWindow::displayError(QAbstractSocket::SocketError)
{
qDebug()<<tcpSocket->errorString();
}

//连接按钮
void MainWindow::on_connectpushButton_clicked()
{
newConnect();
}

发送指令设计：

server.h

#ifndef SERVER_H
#define SERVER_H

#include <QMainWindow>
#include <QDialog>
class QTcpServer;

namespace Ui {
class server;
}

class server : public QMainWindow
{
Q_OBJECT

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

private:
Ui::server *ui;
QTcpServer *tcpServer;
private slots:
void sendMessage();
};

#endif // SERVER_H

server.cpp

#include "server.h"
#include "ui_server.h"
#include <QtNetwork>
server::server(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::server)
{
//QHostAddress &address="10.20.15.101";
ui->setupUi(this);
tcpServer=new QTcpServer(this);
if(!tcpServer->listen(QHostAddress::LocalHost,4196))
{
qDebug()<<"错误"<<tcpServer->errorString();
close();
}
connect(tcpServer,SIGNAL(newConnection()),this,SLOT(sendMessage()));
}

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

void server::sendMessage()
{
QByteArray block;
QDataStream out(&block,QIODevice::WriteOnly);
out.setVersion(QDataStream::Qt_5_6);
out<<(quint16)0;
out<<tr("hello Tcp!");
out.device()->seek(0);
out<<(quint16)(block.size()-sizeof(quint16));
//获取已经建立的连接的套接字
QTcpSocket *clientConnection=tcpServer->nextPendingConnection();
connect(clientConnection,SIGNAL(disconnected()),clientConnection,
SLOT(deleteLater()));
clientConnection->write(block);
clientConnection->disconnectFromHost();
//发送数据
ui->label->setText("send message successful!!!");
}