feat: QNetworkAccessmanager and QNetworkReply and QNetworkRequest

提供网络协议的7层模型中的 中高层的网络协议：Http/FTP/SNMP等

QNetworkAccessmanager  协调网络操作类（处理网络的请求和回应）：负责发送网络请求，创建网络响应
QNetworkRequest        网络请求
QNetworkReply          网络请求的响应（提供finished()/readyRead()/downloadProgress()信号），监测网络响应的执行情况，执行相应的操作

QtHttpEx/ExHttp.cpp

@@ -0,0 +1,108 @@
+#include "ExHttp.h"
+#include "ui_ExHttp.h"
+#include <QMessageBox>
+#include <QDir>
+#include <QDesktopServices>
+
+ExHttp::ExHttp(QWidget *parent) :
+    QMainWindow(parent),
+    ui(new Ui::ExHttp)
+{
+    ui->setupUi(this);
+    setWindowTitle("QNetworkAccessManager 网络管理使用 Http 协议下载");
+
+    m_networkManager = new QNetworkAccessManager(this);
+}
+
+ExHttp::~ExHttp()
+{
+    delete ui;
+}
+
+//下载文件
+void ExHttp::on_btnDown_clicked()
+{
+    QString urlSpec = ui->lineEditUrl->text().trimmed();  //去掉字符串的首尾的空格
+    if (urlSpec.isEmpty()) {
+        QMessageBox::information(this, "提示", "下载地址URL为NULL");
+        return;
+    }
+
+    QUrl url = QUrl::fromUserInput(urlSpec);
+    if (!url.isValid()) {
+        QMessageBox::information(this, "提示", QString("无效URL: %1 \n 错误信息: %2").arg(urlSpec, url.errorString()));
+        return;
+    }
+
+    QString dir = ui->lineEditFile->text().trimmed();
+    if (dir.isEmpty()) {
+        QMessageBox::information(this, "提示", "保存地址为空");
+        return;
+    }
+
+    QString fileFileName = dir + url.fileName(); //文件保存地址 + 文件名
+    if (QFile::exists(fileFileName))
+        QFile::remove(fileFileName);
+
+    m_file = new QFile(fileFileName);    //创建临时文件
+    if (!m_file->open(QIODevice::WriteOnly)) {
+        QMessageBox::information(this, "提示", "打开临时文件错误");
+        return;
+    }
+
+    ui->btnDown->setEnabled(false);
+
+    m_reply = m_networkManager->get(QNetworkRequest(url));  //发送get网络请求，创建网络响应
+    connect(m_reply, SIGNAL(finished()), this, SLOT(onFinished()));
+    connect(m_reply, SIGNAL(readyRead()), this, SLOT(onReadyRead()));
+    connect(m_reply, SIGNAL(downloadProgress(qint64,qint64)), this, SLOT(onDownloadProgress(qint64,qint64)));
+}
+
+//默认的保存路径
+void ExHttp::on_btnFile_clicked()
+{
+    QString currPath = QDir::currentPath();
+    QDir dir(currPath);
+    dir.mkdir("temp");
+
+
+    ui->lineEditFile->setText(currPath + "/temp/");
+}
+
+//网络响应结束
+void ExHttp::onFinished()
+{
+    QFileInfo fileInfo;
+    fileInfo.setFile(m_file->fileName());
+
+    m_file->close();
+    delete m_file;
+    m_file = nullptr;
+
+    m_reply->deleteLater();
+    m_reply = nullptr;
+
+    if (ui->checkBox->isChecked())   //勾选了，下载完成之后，打开下载的文件               //absoluteFilePath() 返回包含文件名的绝对路径。
+        QDesktopServices::openUrl(QUrl::fromLocalFile(fileInfo.absoluteFilePath()));  //使用默认软件的打开下载的文件
+
+    ui->btnDown->setEnabled(true);
+}
+
+//读取下载的数据
+void ExHttp::onReadyRead()
+{
+    m_file->write(m_reply->readAll());   //将返回的数据进行读取，写入到临时文件中
+}
+
+//下载进程
+void ExHttp::onDownloadProgress(qint64 bytesRea, qint64 totalBytes)
+{
+    ui->progressBar->setMaximum(totalBytes);
+    ui->progressBar->setValue(bytesRea);
+}
+
+void ExHttp::on_lineEditUrl_textChanged(const QString &arg1)
+{
+    ui->progressBar->setMaximum(100);
+    ui->progressBar->setValue(0);
+}

QtHttpEx/ExHttp.cpp.autosave

@@ -0,0 +1,109 @@
+#include "ExHttp.h"
+#include "ui_ExHttp.h"
+#include <QMessageBox>
+#include <QDir>
+#include <QDesktopServices>
+
+ExHttp::ExHttp(QWidget *parent) :
+    QMainWindow(parent),
+    ui(new Ui::ExHttp)
+{
+    ui->setupUi(this);
+    setWindowTitle("QNetworkAccessManager 网络管理使用 Http 协议下载");
+
+    m_networkManager = new QNetworkAccessManager(this);
+    m_reply = nullptr;
+    m_file = nullptr;
+}
+
+ExHttp::~ExHttp()
+{
+    delete ui;
+}
+
+//下载文件
+void ExHttp::on_btnDown_clicked()
+{
+    QString urlSpec = ui->lineEditUrl->text().trimmed();  //去掉字符串的首尾的空格
+    if (urlSpec.isEmpty()) {
+        QMessageBox::information(this, "提示", "下载地址URL为NULL");
+        return;
+    }
+
+    QUrl url = QUrl::fromUserInput(urlSpec);
+    if (!url.isValid()) {
+        QMessageBox::information(this, "提示", QString("无效URL: %1 \n 错误信息: %2").arg(urlSpec, url.errorString()));
+        return;
+    }
+
+    QString dir = ui->lineEditFile->text().trimmed();
+    if (dir.isEmpty()) {
+        QMessageBox::information(this, "提示", "保存地址为空");
+        return;
+    }
+
+    QString fileFileName = dir + url.fileName(); //文件保存地址 + 文件名
+    if (QFile::exists(fileFileName))
+        QFile::remove(fileFileName);
+
+    m_file = new QFile(fileFileName);    //创建临时文件
+    if (!m_file->open(QIODevice::WriteOnly)) {
+        QMessageBox::information(this, "提示", "打开临时文件错误");
+        return;
+    }
+
+    ui->btnDown->setEnabled(false);
+
+    m_reply = m_networkManager->get(QNetworkRequest(url));  //发送get网络请求，创建网络响应
+    connect(m_reply, SIGNAL(finished()), this, SLOT(onFinished()));
+    connect(m_reply, SIGNAL(readyRead()), this, SLOT(onReadyRead()));
+    connect(m_reply, SIGNAL(downloadProgress(qint64,qint64)), this, SLOT(onDownloadProgress(qint64,qint64)));
+}
+
+//默认的保存路径
+void ExHttp::on_btnFile_clicked()
+{
+    QString currPath = QDir::currentPath();
+    QDir dir(currPath);
+    dir.mkdir("temp");
+
+    ui->lineEditFile->setText(currPath + "/temp/");
+}
+
+//网络响应结束
+void ExHttp::onFinished()
+{
+    QFileInfo fileInfo;
+    fileInfo.setFile(m_file->fileName());
+
+    m_file->close();
+    delete m_file;
+    m_file = nullptr;
+
+    m_reply->deleteLater();
+    m_reply = nullptr;
+
+    if (ui->checkBox->isChecked())   //勾选了，下载完成之后，打开下载的文件               //absoluteFilePath() 返回包含文件名的绝对路径。
+        QDesktopServices::openUrl(QUrl::fromLocalFile(fileInfo.absoluteFilePath()));  //使用默认软件的打开下载的文件
+
+    ui->btnDown->setEnabled(true);
+}
+
+//读取下载的数据
+void ExHttp::onReadyRead()
+{
+    m_file->write(m_reply->readAll());   //将返回的数据进行读取，写入到临时文件中
+}
+
+//下载进程
+void ExHttp::onDownloadProgress(qint64 bytesRea, qint64 totalBytes)
+{
+    ui->progressBar->setMaximum(totalBytes);
+    ui->progressBar->setValue(bytesRea);
+}
+
+void ExHttp::on_lineEditUrl_textChanged(const QString &arg1)
+{
+    ui->progressBar->setMaximum(100);
+    ui->progressBar->setValue(0);
+}

QtHttpEx/ExHttp.h

@@ -0,0 +1,40 @@
+#ifndef EXHTTP_H
+#define EXHTTP_H
+
+#include <QMainWindow>
+#include <QNetworkAccessManager>
+#include <QNetworkReply>
+#include <QFile>
+#include <QUrl>
+#include <QDir>
+
+namespace Ui {
+class ExHttp;
+}
+
+class ExHttp : public QMainWindow
+{
+    Q_OBJECT
+
+public:
+    explicit ExHttp(QWidget *parent = nullptr);
+    ~ExHttp();
+
+private slots:
+    void on_btnDown_clicked();  //下载文件
+    void on_btnFile_clicked();  //默认的保存路径
+    void on_lineEditUrl_textChanged(const QString &arg1);
+
+    void onFinished();          //网络响应结束
+    void onReadyRead();         //读取下载的数据
+    void onDownloadProgress(qint64 bytesRea, qint64 totalBytes);  //下载进程
+
+private:
+    Ui::ExHttp *ui;
+
+    QNetworkAccessManager* m_networkManager;   //网络管理
+    QNetworkReply* m_reply;                    //网络响应
+    QFile* m_file;                             //下载保存的临时文件
+};
+
+#endif // EXHTTP_H

QtHttpEx/ExHttp.ui

@@ -0,0 +1,89 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>ExHttp</class>
+ <widget class="QMainWindow" name="ExHttp">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>555</width>
+    <height>111</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>ExHttp</string>
+  </property>
+  <widget class="QWidget" name="centralWidget">
+   <layout class="QGridLayout" name="gridLayout_2">
+    <item row="0" column="0">
+     <layout class="QGridLayout" name="gridLayout" rowstretch="1,8,1">
+      <item row="1" column="1">
+       <widget class="QLineEdit" name="lineEditFile"/>
+      </item>
+      <item row="1" column="2">
+       <widget class="QPushButton" name="btnFile">
+        <property name="text">
+         <string>默认路径</string>
+        </property>
+       </widget>
+      </item>
+      <item row="0" column="1">
+       <widget class="QLineEdit" name="lineEditUrl">
+        <property name="text">
+         <string>http://download.qt.io/archive/vsaddin/2.4.2/md5sums.txt</string>
+        </property>
+       </widget>
+      </item>
+      <item row="0" column="0">
+       <widget class="QLabel" name="label">
+        <property name="text">
+         <string>URL：</string>
+        </property>
+        <property name="alignment">
+         <set>Qt::AlignRight|Qt::AlignTrailing|Qt::AlignVCenter</set>
+        </property>
+       </widget>
+      </item>
+      <item row="0" column="2">
+       <widget class="QPushButton" name="btnDown">
+        <property name="text">
+         <string>下载</string>
+        </property>
+       </widget>
+      </item>
+      <item row="1" column="0">
+       <widget class="QLabel" name="label_2">
+        <property name="text">
+         <string>保存路径：</string>
+        </property>
+       </widget>
+      </item>
+      <item row="2" column="0" colspan="2">
+       <widget class="QProgressBar" name="progressBar">
+        <property name="value">
+         <number>0</number>
+        </property>
+        <property name="textVisible">
+         <bool>true</bool>
+        </property>
+        <property name="textDirection">
+         <enum>QProgressBar::TopToBottom</enum>
+        </property>
+       </widget>
+      </item>
+      <item row="2" column="2">
+       <widget class="QCheckBox" name="checkBox">
+        <property name="text">
+         <string>结束之后打开</string>
+        </property>
+       </widget>
+      </item>
+     </layout>
+    </item>
+   </layout>
+  </widget>
+ </widget>
+ <layoutdefault spacing="6" margin="11"/>
+ <resources/>
+ <connections/>
+</ui>

QtHttpEx/QtHttpEx.pro

@@ -0,0 +1,56 @@
+#-------------------------------------------------
+#
+# Project created by QtCreator 2019-12-05T21:58:28
+#
+#-------------------------------------------------
+
+QT       += core gui network
+
+greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
+
+TARGET = QtHttpEx
+TEMPLATE = app
+
+# The following define makes your compiler emit warnings if you use
+# any feature of Qt which has been marked as deprecated (the exact warnings
+# depend on your compiler). Please consult the documentation of the
+# deprecated API in order to know how to port your code away from it.
+DEFINES += QT_DEPRECATED_WARNINGS
+
+# You can also make your code fail to compile if you use deprecated APIs.
+# In order to do so, uncomment the following line.
+# You can also select to disable deprecated APIs only up to a certain version of Qt.
+#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
+
+CONFIG += c++11
+
+SOURCES += \
+        main.cpp \
+        ExHttp.cpp
+
+HEADERS += \
+        ExHttp.h
+
+FORMS += \
+        ExHttp.ui
+
+macx {
+ICON = images/icon.icns
+}
+
+unix:!macx{
+# linux only
+}
+
+win32 {
+RC_ICONS = images/icon.ico
+}
+
+
+# Default rules for deployment.
+qnx: target.path = /tmp/$${TARGET}/bin
+else: unix:!android: target.path = /opt/$${TARGET}/bin
+!isEmpty(target.path): INSTALLS += target
+
+RESOURCES += \
+    resources.qrc

QtHttpEx/main.cpp

@@ -0,0 +1,11 @@
+#include "ExHttp.h"
+#include <QApplication>
+
+int main(int argc, char *argv[])
+{
+    QApplication a(argc, argv);
+    ExHttp w;
+    w.show();
+
+    return a.exec();
+}

QtHttpEx/resources.qrc

@@ -0,0 +1,6 @@
+<RCC>
+    <qresource prefix="/">
+        <file>images/Image6.png</file>
+        <file>images/Image3.png</file>
+    </qresource>
+</RCC>

README.md

@@ -75,8 +75,9 @@
 
 ## 第四部分：网络编程
 
-- 主机信息查询QHostInfo和QNetworkInterface查询IP等【QtQHostInfoEx】
-- TCP通信之QTcpServer和QTcpSocket，服务器和客户端通讯【QtTcpEx】
+- 主机信息查询`QHostInfo`和`QNetworkInterface`查询IP等【QtQHostInfoEx】
+- `TCP`通信之`QTcpServer`和`QTcpSocket`，服务器和客户端通讯【QtTcpEx】
+- `QNetworkAccessManager`/`QNetworkReply`/`QNetworkRequest`实现高层网络的操作
 
 <br>