文章目录
- 项目:网路
- 项目1:主机信息查询
- 1.1 QHostInfo类和QNetworkInterface类
- 1.2 主机信息查询项目实现
- 项目2:基于HTTP的网络应用程序
- 2.1 项目中用到的函数详解
- 2.2 主要源码
项目:网路
项目1:主机信息查询
使用QHostInfo类和QNetworkInterface类可以获取主机的一些网络信息,如IP地址1和MAC地址2。
在Qt项目里使用Qt Network模块,需要在项目配置文件(.pro 文件)中增加一条配置语句:
QT += network
1.1 QHostInfo类和QNetworkInterface类
QHostInfo类常用函数
QHostInfo类可以根据主机名获取主机的IP地址,或者通过IP地址获取主机名。
- [static] QString QHostInfo::localHostName():返回本机主机名;
- [static] QString QHostInfo::localDomainName():返回本机域名系统(domain name system,DNS)域名;
- [static] QHostInfo QHostInfo::fromName(const QString &name):返回指定主机名的IP地址;
- [static] int QHostInfo::lookupHost(const QString &name, QObject *receiver, const char *member):以异步的方式根据主机名查找主机的IP地址,并返回一个表示本次查找的ID,可用作abortHostLookup()函数的参数;
- [static] void QHostInfo::abortHostLookup(int id):使用 lookupHost() 返回的 ID 终止主机查找。
- QList<QHostAddress> QHostInfo::addresses() const:返回与hostName()对应主机关联的IP地址列表;
- QString QHostInfo::hostName() const:返回通过IP地址查找到的主机名;
QNetworkInterface类常用的函数
QNetworkInterface类可以获得运行程序的主机名的所用IP地址和网络接口列表。
- [static] QList QNetworkInterface::allAddresses():返回主机上所有IP地址的列表(如果不需要知道子网掩码和广播地址);
- [static] QList QNetworkInterface::allInterfaces():返回主机上所有网络接口列表(一个网络接口可能包含多个IP地址,每个IP地址与掩码或广播地址关联);
- QList QNetworkInterface::addressEntries() const:返回网络接口的IP地址列表,包括子网掩码和广播地址;
- QString QNetworkInterface::hardwareAddress() const:返回接口的低级硬件地址,以太网里就是MAC地址;
- bool QNetworkInterface::isValid() const:如果接口信息有效就返回true;
- QNetworkInterface::InterfaceType QNetworkInterface::type() const:返回网络接口的类型;
1.2 主机信息查询项目实现
- 显示本机地址信息
//获取本机主机名和IP地址按钮
void Widget::on_btnGetHostInfo_clicked()
{ui->plainTextEdit->clear();QString hostName = QHostInfo::localHostName(); //本机主机名qDebug()<<hostName;ui->plainTextEdit->appendPlainText("HostName:"+hostName+"\n");QHostInfo hostInfo = QHostInfo::fromName(hostName); //本机IP地址QList<QHostAddress> addrList = hostInfo.addresses();//IP地址列表if(addrList.isEmpty()) return;foreach(QHostAddress host, addrList){bool show = ui->checkBox_OnlyIPV4->isChecked(); //只显示ipv4//Returns the network layer protocol of the host address.show = show ? (host.protocol() == QAbstractSocket::IPv4Protocol):true;if(show){ui->plainTextEdit->appendPlainText("protool:"+protocolName(host.protocol()));//协议ui->plainTextEdit->appendPlainText("HostIPAdddress:"+host.toString());ui->plainTextEdit->appendPlainText(QString("isGolbal() = %1\n").arg(host.isGlobal()));}}
}
protocol()函数:返回主机地址的网络层协议。
QAbstractSocket::NetworkLayerProtocol QHostAddress::protocol() const
Returns the network layer protocol of the host address.
isGlobal()函数:如果地址是 IPv4 或 IPv6 全局地址,则返回 true,否则返回 false。全局地址是不为特殊目的(如环回或多播)或未来目的保留的地址。
bool QHostAddress::isGlobal() const
Returns true if the address is an IPv4 or IPv6 global address, false otherwise. A global address is an address that is not reserved for special purposes (like loopback or multicast) or future purposes.
自定义函数protocolName(),通过协议类型返回协议名称字符串。
//通过协议类型返回协议名称字符串
QString Widget::protocolName(QAbstractSocket::NetworkLayerProtocol protocol)
{switch (protocol) {case QAbstractSocket::IPv4Protocol:return "IPV4";case QAbstractSocket::IPv6Protocol:return "IPV6";case QAbstractSocket::AnyIPProtocol:return "Any Internet Protocol";default:return "Unknown NetWork Layer Protocol";}
}
- 查找主机地址信息
[static] int QHostInfo::lookupHost(const QString &name, QObject *receiver, const char *member): name表示主机名的字符串,可以是主机名、域名或IP地址;receive和member指定接收者和槽函数名称。
//查找域名的IP地址
void Widget::on_btnLookkup_clicked()
{ui->plainTextEdit->clear();QString hostName = ui->comboBox->currentText(); //读取主机名ui->plainTextEdit->appendPlainText("Searching for host information:"+hostName+"\n");QHostInfo::lookupHost(hostName, this,SLOT(do_lookedUpHostInfo(QHostInfo)));
}//查找主机信息的槽函数
void Widget::do_lookedUpHostInfo(const QHostInfo &host)
{QList<QHostAddress> addrList = host.addresses(); //获取主机地址列表if(addrList.isEmpty())return;foreach(QHostAddress host, addrList){bool show = ui->checkBox_OnlyIPV4->isChecked(); //只显示ipv4//Returns the network layer protocol of the host address.show = show ? (host.protocol() == QAbstractSocket::IPv4Protocol):true;if(show){ui->plainTextEdit->appendPlainText("protool:"+protocolName(host.protocol()));//协议ui->plainTextEdit->appendPlainText(host.toString());ui->plainTextEdit->appendPlainText(QString("isGolbal() = %1\n").arg(host.isGlobal()));}}
}
- QNetworkInterface类的使用
//根据枚举值返回字符串
QString Widget::interfaceType(QNetworkInterface::InterfaceType type)
{switch(type){case QNetworkInterface::Unknown:return "Unkown";case QNetworkInterface::Loopback:return "Loopback";case QNetworkInterface::Ethernet:return "Etherent";case QNetworkInterface::Wifi:return "Wifi";default:return "Other type";}
}//allInterfaces()
void Widget::on_btnAllInterface_2_clicked()
{ui->plainTextEdit->clear();QList<QNetworkInterface> list = QNetworkInterface::allInterfaces();//网络接口列表foreach(QNetworkInterface interface,list){if(!interface.isValid())continue;
// The name of the device
// Hardware devices
// Interface type
// Subnet mask
// broadcast addressui->plainTextEdit->appendPlainText("The name of the device:"+interface.humanReadableName());ui->plainTextEdit->appendPlainText("Hardware devices:"+interface.hardwareAddress());ui->plainTextEdit->appendPlainText("Interface type:"+interfaceType(interface.type()));QList<QNetworkAddressEntry> entryList = interface.addressEntries();//地址列表foreach(QNetworkAddressEntry entry, entryList){ui->plainTextEdit->appendPlainText(" IP Address:"+entry.ip().toString());ui->plainTextEdit->appendPlainText(" Subnet mask:"+entry.netmask().toString());ui->plainTextEdit->appendPlainText(" broadcast address:"+entry.broadcast().toString()+"\n");}}
}//alladdress
void Widget::on_btnAllAddress_clicked()
{ui->plainTextEdit->clear();QList<QHostAddress> addrelist = QNetworkInterface::allAddresses();//IP地址列表if(addrelist.isEmpty()) return;foreach(QHostAddress host, addrelist){bool show = ui->checkBox_OnlyIPV4->isChecked();show = show ? (host.protocol() == QAbstractSocket::IPv4Protocol):true;if(show){ui->plainTextEdit->appendPlainText("protocol:"+protocolName(host.protocol()));ui->plainTextEdit->appendPlainText("IP Address:"+host.toString());ui->plainTextEdit->appendPlainText(QString("isGrobal() = %1\n").arg(host.isGlobal()));}}
}
Loopback:
回送地址(Loopback Address)是本机回送地址(127.X.X.X),即主机IP堆栈内部的IP地址,主要用于网络软件测试以及本地机进程间通信。因此,无论什么程序,一旦使用回送地址发送数据,协议软件会立即将其返回,不进行任何网络传输。127.0.0.1是回送地址,又指本地机,一般用来测试使用。
项目2:基于HTTP的网络应用程序
QNetworkRequest 类通过 URL 发起网络协议请求,其也保存网络请求的信息,目前支持 HTTP、
FTP 和本地文件 URL 的下载或上传。
QNetworkAccessManager 类用于协调网络操作,在 QNetworkRequest 发起网络请求后,
QNetworkAccessManager 负责发送网络请求,以及创建网络响应。
QNetworkReply 类表示网络请求的响应,由 QNetworkAccessManager 在发送网络请求后创建网
络响应。QNetworkReply 提供的信号 finished()、readyRead()、downloadProgress()可用于监测网络响
应的执行情况,从而进行相应的操作。
2.1 项目中用到的函数详解
-
clearButtonEnabled : bool
此属性用于保存行编辑在不为空时是否显示清除按钮。
如果启用,行编辑在包含一些文本时会显示一个尾随清除按钮,否则,行编辑不会显示清除按钮(默认值)。 -
默认路径按钮功能:
- [static] QString QDir::currentPath()
返回应用进程当前目录的绝对路径。当前目录是使用 QDir::setCurrent() 设置的最后一个目录,或者,如果从未调用过,则为父进程启动此应用进程的目录。 - bool QDir::mkdir(const QString &dirName) const
创建一个名为 dirName 的子目录。
- 下载按钮功能:
- QString QString::trimmed() const
返回一个字符串,该字符串删除了开头和结尾的空格。 - [static] QUrl QUrl::fromUserInput(const QString &userInput)
从用户提供的 userInput 字符串返回有效的 URL(如果可以扣除)。如果不可能,则返回无效的 QUrl()。 - QString QUrl::errorString() const
如果修改此 QUrl 对象的最后一个操作遇到解析错误,则返回错误消息。如果未检测到错误,则此函数返回一个空字符串,isValid() 返回 true。 - QString QUrl::fileName(QUrl::ComponentFormattingOptions options = FullyDecoded) const
返回文档名,不包括目录路径。 - bool QFile::remove()
删除 fileName() 指定的文档。如果成功,则返回 true;否则返回 false。文档在删除之前已关闭。 - QNetworkReply *QNetworkAccessManager::get(const QNetworkRequest &request)
发布一个请求以获取目标请求的内容,并返回一个新的 QNetworkReply 对象,该对象打开以供读取,每当新数据到达时,该对象都会发出 readyRead() 信号。将下载内容以及相关的标题。 - [signal] void QIODevice::readyRead()
每当有新数据可用时,此信号就会发出一次从设备的当前读取信道读取。只有当有新数据可用时,它才会再次发出,例如,当新的网络数据有效负载到达您的网络套接字时,或者当新的数据块附加到您的设备时。 - [signal] void QNetworkReply::downloadProgress(qint64 bytesReceived, qint64 bytesTotal)
发出此信号以指示此网络请求的下载部分的进度(如果有)。如果没有与此请求关联的下载,则此信号将发出一次,其中 0 作为 bytesReceived 和 bytesTotal 的值。 - [signal] void QNetworkReply::finished()
当回复完成处理时,将发出此信号。发出此信号后,回复的数据或元数据将不再更新。
- 读取下载数据
-
qint64 QIODevice::write(const char *data, qint64 maxSize)
将数据中最多 maxSize 字节的数据写入设备。返回实际写入的字节数,如果发生错误,则返回 -1。 -
QByteArray QIODevice::readAll()
从设备读取所有剩余数据,并将其作为字节数组返回。
2.2 主要源码
头文件
#ifndef WIDGET_H
#define WIDGET_H#include <QWidget>
#include <QNetworkAccessManager>
#include <QFile>
#include <QMessageBox>
#include <QIODevice>
#include <QNetworkReply>
#include <QDesktopServices>
#include <QFileInfo>
#include <QUrl>namespace Ui {
class Widget;
}class Widget : public QWidget
{Q_OBJECT
private:QNetworkAccessManager networkManager; //网络管理QNetworkReply *reply; //网络响应QFile *downloadedFile; //下载保存的临时文件
public:explicit Widget(QWidget *parent = nullptr);~Widget();
private slots:void do_finished();void do_readyRead();void do_downloadProgress(qint64 bytesRead, qint64 totalBytes);void on_btnDownload_clicked();void on_btnDefaultPath_clicked();void on_editURL_textChanged(const QString &arg1);private:Ui::Widget *ui;
};#endif // WIDGET_H
源文件
#include "widget.h"
#include "ui_widget.h"#include <QDir>Widget::Widget(QWidget *parent) :QWidget(parent),ui(new Ui::Widget)
{ui->setupUi(this);
//clearButtonEnabled : bool
//This property holds whether the line edit displays a clear button when it is not empty.
//If enabled, the line edit displays a trailing clear button when it contains some text,
// otherwise the line edit does not show a clear button (the default).ui->editURL->setClearButtonEnabled(true);this->setLayout(ui->verticalLayout);
}Widget::~Widget()
{delete ui;
}void Widget::do_finished()
{//网络响应结束QFileInfo fileInfo(downloadedFile->fileName()); //获取下载文件的文件名downloadedFile->close();delete downloadedFile; //删除临时文件reply->deleteLater(); //由主事件循环删除此文件对象if(ui->checkBoxOpen->isChecked()){QDesktopServices::openUrl(QUrl::fromLocalFile(fileInfo.absoluteFilePath()));}ui->btnDownload->setEnabled(true);
}void Widget::do_readyRead()
{//读取下载数据downloadedFile->write(reply->readAll());
// qint64 QIODevice::write(const char *data, qint64 maxSize)
// Writes at most maxSize bytes of data from data to the device.
// Returns the number of bytes that were actually written,
// or -1 if an error occurred.
// QByteArray QIODevice::readAll()
// Reads all remaining data from the device, and returns it as a byte array.}void Widget::do_downloadProgress(qint64 bytesRead, qint64 totalBytes)
{//下载进度ui->progressBar->setMaximum(totalBytes);//Holds the total amount of data to download in bytes.ui->progressBar->setValue(bytesRead);
}//默认了路径 按钮
void Widget::on_btnDefaultPath_clicked()
{
// [static] QString QDir::currentPath()
// Returns the absolute path of the application's current directory.
// The current directory is the last directory set with QDir::setCurrent() or,
// if that was never called,
// the directory at which this application was started at by the parent process.QString curPath = QDir::currentPath(); //返回当前绝对路径给QString变量QDir dir(curPath); //定义QDir变量QString sub = "temp";
// bool QDir::mkdir(const QString &dirName) const
// Creates a sub-directory called dirName.dir.mkdir(sub); //当前路径下创立名为sub的文件夹ui->editPath->setText(curPath+"/"+sub+"/"); //设置lineedit的文字
}//下载按钮,开始下载
void Widget::on_btnDownload_clicked()
{
// QString QString::trimmed() const
// Returns a string that has whitespace removed from the start and the end.QString urlSpec = ui->editURL->text().trimmed(); //将editURL中的文字给QString变量赋值//urlspec判空if(urlSpec.isEmpty()){QMessageBox::information(this,"error","Please specify the download address");return;}
// [static] QUrl QUrl::fromUserInput(const QString &userInput)
// Returns a valid URL from a user supplied userInput string if one can be deducted.
// In the case that is not possible, an invalid QUrl() is returned.QUrl newUrl = QUrl::fromUserInput(urlSpec); //从urlSpaec里获取url//newurl判有效if(!newUrl.isValid()){
// QString QUrl::errorString() const
// Returns an error message if the last operation that modified this QUrl object ran into a parsing error.
// If no error was detected,
// this function returns an empty string and isValid() returns true.QString info = "The URL is invalid:"+urlSpec+"\n error:"+newUrl.errorString();QMessageBox::information(this,"error",info);return;}QString tempDir = ui->editPath->text().trimmed(); //临时目录if(tempDir.isEmpty()){QMessageBox::information(this,"error","Please specify the download address");return;}QString fullFileName = tempDir + newUrl.fileName(); //文件名
// QString QUrl::fileName(QUrl::ComponentFormattingOptions options = FullyDecoded) const
// Returns the name of the file, excluding the directory path.if(QFile::exists(fullFileName)){ //如果文件存在QFile::remove(fullFileName); //删除文件
// bool QFile::remove()
// Removes the file specified by fileName(). Returns true if successful; otherwise returns false.
// The file is closed before it is removed.}downloadedFile = new QFile(fullFileName); //创建临时文件if(!downloadedFile->open(QIODevice::WriteOnly)){QMessageBox::information(this,"error","Temporary file open error");}ui->btnDownload->setEnabled(false);//发送网络请求,创建网络相应reply = networkManager.get(QNetworkRequest(newUrl)); //网络响应从网络管理里面获取网络请求
// QNetworkReply *QNetworkAccessManager::get(const QNetworkRequest &request)
// Posts a request to obtain the contents of the target request and
// returns a new QNetworkReply object opened for reading
// which emits the readyRead() signal whenever new data arrives.
// The contents as well as associated headers will be downloaded.
// QObject *QObject::parent() const
// Returns a pointer to the parent object.connect(reply, SIGNAL(readyRead()), this, SLOT(do_readyRead()));connect(reply, SIGNAL(downloadProgress(qint64,qint64)),this, SLOT(do_downloadProgress(qint64,qint64)));connect(reply, SIGNAL(finished()), this, SLOT(do_finished()));
// [signal] void QIODevice::readyRead()
// This signal is emitted once every time new data is available for
// reading from the device's current read channel.
// It will only be emitted again once new data is available,
// such as when a new payload of network data has arrived on your network socket,
// or when a new block of data has been appended to your device.
// [signal] void QNetworkReply::downloadProgress(qint64 bytesReceived, qint64 bytesTotal)
// This signal is emitted to indicate the progress of the download part of
// this network request, if there's any. If there's no download associated with this request,
// this signal will be emitted once with 0 as the value of both bytesReceived and bytesTotal.
// [signal] void QNetworkReply::finished()
// This signal is emitted when the reply has finished processing.
// After this signal is emitted, there will be no more updates to the reply's data or metadata.
}void Widget::on_editURL_textChanged(const QString &arg1)
{Q_UNUSED(arg1);ui->progressBar->setMaximum(100);ui->progressBar->setValue(0);
}
IP地址(Internet Protocol Address)是指互联网协议地址,又译为网际协议地址。IP地址是IP协议提供的一种统一的地址格式,它为互联网上的每一个网络和每一台主机分配一个逻辑地址,以此来屏蔽物理地址的差异。 ↩︎
MAC地址(英语:Media Access Control Address),直译为媒体存取控制位址,也称为局域网地址(LAN Address),MAC位址,以太网地址(Ethernet Address)或物理地址(Physical Address),它是一个用来确认网络设备位置的位址。在OSI模型中,第三层网络层负责IP地址,第二层数据链路层则负责MAC位址。MAC地址用于在网络中唯一标示一个网卡,一台设备若有一或多个网卡,则每个网卡都需要并会有一个唯一的MAC地址。 ↩︎