QNetworkInformation Class

#include <QCoreApplication>#include <QNetworkInformation> #include<QDebug>voidonReachabilityChanged(QNetworkInformation::Reachability reachability) {switch(reachability) {caseQNetworkInformation::Reachability::Unknown：        qDebug() << "Network reachability is unknown.";
       break;caseQNetworkInformation::Reachability::Disconnected：        qDebug() << "Network is disconnected.";
       break;caseQNetworkInformation::Reachability::Local：        qDebug() << "Network is locally reachable.";
       break;caseQNetworkInformation::Reachability::Site：        qDebug() << "Network can reach the site.";
       break;caseQNetworkInformation::Reachability::Online：        qDebug() << "Network is online.";
       break; } }intmain(intargc, char *argv[]) { QCoreApplicationa(argc,argv);// 检查是否支持 QNetworkInformation if(！QNetworkInformation::loadDefaultBackend()) {        qWarning() << "QNetworkInformation is not supported on this platform or backend.";
       返回 1; } QNetworkInformation* netInfo=QNetworkInformation::instance();// 连接到 reachabilityChanged 信号   QObject连接（netInfo, &QNetworkInformation::reachabilityChanged, &onReachabilityChanged);// 打印初始状态onReachabilityChanged(netInfo->reachability());returna.exec(); }

// 判断 IP 地址是否为 "本地 "的简单助手boolisLocalAddress(constQHostAddress&address) {returnaddress.isInSubnet(QHostAddress("192.168.0.0"), 16)||address.isInSubnet(QHostAddress("10.0.0.0"), 8)    ||address.isInSubnet(QHostAddress("172.16.0.0"), 12) ||address.isLoopback(); }intmain(intargc, char *argv[]) { ...// 目标 IP 地址（默认：谷歌 DNS  QStringtargetIpStr=argc> 1 ?argv[1]:"8.8.8.8"；    QHostAddresstargetIp(targetIpStr);if(targetIp.isNull()) {        qWarning() << "Invalid IP address:" << targetIpStr;
       return 1; }// 决定目标所需的可达性级别   QNetworkInformation::Reachability requiredReachability=isLocalAddress(targetIp)?QNetworkInformation::Reachability::Local ： QNetworkInformation::Reachability::Online;//获取当前系统报告的可达性   QNetworkInformation::Reachability currentReachability=  networkInfo->reachability()；
    qDebug() << "Target IP:" << targetIp.toString();
    qDebug() << "Target is considered"
            <<(isLocalAddress(targetIp)? "本地/站点。:"外部/在线"）；    qDebug() << "Required reachability level:" << requiredReachability;
    qDebug() << "Current reachability:" << currentReachability;

   如果(currentReachability<requiredReachability) {        qWarning() << "Current network state may not allow reaching the target address.";
   否则{        qDebug() << "Target may be reachable based on current network state.";
    } ...