上一篇文章已经打通了数据源之一的串口采集,这次要说的是网络采集,网络通信目前用的最多的是三种,TCP/UDP/HTTP,其中tcp通信又包括了客户端服务端两种,tcp通信才用了多次握手机制不丢包,但是耗费资源多而且需要建立连接。udp通信在大数据量或者网络不稳定的情况下,可能丢包,而且顺序无法保证,但是一个包的数据肯定是正确的,由于占用资源极少而且不需要建立连接,在很多场景中应用也蛮多,我个人用udp以来,也没发现过丢包的情况,可能数据量不够大或者是在局域网内的原因吧,反正用起来还是蛮爽的。http通信目前非常流行,尤其是和服务器之间做数据交互,基本上post请求然后返回一串json数据,解析对应的json数据即可。本次采用的TCP通信作为示例,其他两种可以自行拓展,也很简单的。
void frmData::initServer()
{
//实例化串口类,绑定信号槽
com = new QextSerialPort(QextSerialPort::EventDriven, this);
connect(com, SIGNAL(readyRead()), this, SLOT(readDataCom()));
//实例化网络通信客户端类,绑定信号槽
tcpClient = new QTcpSocket(this);
connect(tcpClient, SIGNAL(readyRead()), this, SLOT(readDataClient()));
//实例化网络通信服务端类,绑定信号槽
tcpSocket = NULL;
tcpServer = new QTcpServer(this);
connect(tcpServer, SIGNAL(newConnection()), this, SLOT(newConnection()));
//开启定时器读取数据库采集数据
timer = new QTimer(this);
connect(timer, SIGNAL(timeout()), this, SLOT(readDataDb()));
timer->setInterval(1000);
}
void frmData::on_btnOpenTcpClient_clicked()
{
if (ui->btnOpenTcpClient->text() == "连接") {
tcpClient->connectToHost(App::TcpServerIP, App::TcpServerPort);
bool ok = tcpClient->waitForConnected(1000);
if (ok) {
setEnable(ui->btnOpenTcpClient, false);
ui->btnOpenTcpClient->setText("断开");
}
} else {
tcpClient->disconnectFromHost();
setEnable(ui->btnOpenTcpClient, true);
ui->btnOpenTcpClient->setText("连接");
}
}
void frmData::on_btnOpenTcpServer_clicked()
{
if (ui->btnOpenTcpServer->text() == "监听") {
#if (QT_VERSION > QT_VERSION_CHECK(5,0,0))
bool ok = tcpServer->listen(QHostAddress::AnyIPv4, App::TcpListenPort);
#else
bool ok = tcpServer->listen(QHostAddress::Any, App::TcpListenPort);
#endif
if (ok) {
setEnable(ui->btnOpenTcpServer, false);
ui->btnOpenTcpServer->setText("停止");
}
} else {
if (tcpSocket != NULL) {
tcpSocket->disconnectFromHost();
}
tcpSocket = NULL;
tcpServer->close();
setEnable(ui->btnOpenTcpServer, true);
ui->btnOpenTcpServer->setText("监听");
}
}
void frmData::readDataClient()
{
QByteArray data = tcpClient->readAll();
if (data.length() <= 0) {
return;
}
//默认取第一个字节解析,可以自行更改
quint8 value = data.at(0);
ui->txtValue->setText(QString::number(value));
append(3, data.toHex());
}
void frmData::readDataServer()
{
QByteArray data = tcpSocket->readAll();
if (data.length() <= 0) {
return;
}
//默认取第一个字节解析,可以自行更改
quint8 value = data.at(0);
ui->txtValue->setText(QString::number(value));
append(3, data.toHex());
}
void frmData::newConnection()
{
while(tcpServer->hasPendingConnections()) {
if (tcpSocket != NULL) {
tcpSocket->disconnectFromHost();
}
tcpSocket = tcpServer->nextPendingConnection();
connect(tcpSocket, SIGNAL(readyRead()), this, SLOT(readDataServer()));
}
}