QT中网页（http）请求与下载

首先需要pro里面加上network

QT += core gui network

第一种方法

一，获取LineEdit网址内容并传值

QString url=ui->lineEdit->text();
manager->get(QNetworkRequest(QUrl(url)));

二，连接信号

connect(manager,SIGNAL(finished(QNetworkReply *)),this,SLOT(doProcessFinished(QNetworkReply *)));

三，打印出内容

QString str=reply->readAll();
ui->textEdit->setText(str);

代码：

.h代码
private slots:
void buttonnn();
void doProcessFinished(QNetworkReply *reply)
private:
QNetworkAccessManager *manager;
QNetworkReply *reply;
void Init();

.cpp代码：

void Widget::Init()          //需要添加到主函数里

    manager=new QNetworkAccessManager(this);

    connect(manager,SIGNAL(finished(QNetworkReply *)),this,SLOT(doProcessFinished(QNetworkReply *)));

void Widget::buttonnn()            //需要连接信号槽

    QString url=ui->lineEdit->text();

    manager->get(QNetworkRequest(QUrl(url)));

void Widget::doProcessFinished(QNetworkReply *reply)

    QString str=reply->readAll();

    qDebug()<<str;

   ui->textEdit->setText(str);

第二种方法

比第一种主要多了一个判断错误的方法。

errorr(QNetworkReply::NetworkError error)

.h代码
private slots:
void buttonnn();
void doRead();
void errorr(QNetworkReply::NetworkError);
void doFinished();
private:
QNetworkAccessManager *manager;
QNetworkReply *reply;

void Init();

.cpp代码

void Widget::Init()

    manager= new QNetworkAccessManager(this);

void Widget::buttonnn()

    QNetworkRequest request;

    request.setRawHeader(QByteArray("wqeqeqq"),QByteArray("vvvvvvvv"));

    QString url=ui->lineEdit->text();

    QUrl s;

    s.setUrl(url);

    request.setUrl(s);

    reply=manager->get(request);

    connect(reply ,SIGNAL(readyRead()),this,SLOT(doRead()));

    connect(reply,SIGNAL(error(QNetworkReply::NetworkError)),this,SLOT(errorr(QNetworkReply::NetworkError)));

    connect(reply,SIGNAL(finished()),this,SLOT(doFinished()));

void Widget::doRead()

    QString str=reply->readAll();

    ui->textEdit->setText(str);

void Widget::errorr(QNetworkReply::NetworkError error)

    switch ((int)error) {

    case  QNetworkReply::ContentGoneError:

         qDebug()<<11111;

    case  QNetworkReply::ContentReSendError:

        qDebug()<<2222;

    default:

        break;

void Widget::doFinished()

    qDebug()<<3333;

下载：

主要增加了这一个函数

void Widget::doRead()
{
while(!reply->atEnd())
{
QByteArray ba=reply->readAll();
myfile->write(ba);
}
}

文件打开写入

QStringList list=url.split("/");
QString filename=list.at(list.length()-1);

myfile->setFileName(filename);
bool ret=myfile->open(QIODevice::WriteOnly |QIODevice::Truncate);

设置进度条的函数

void Widget::downLoad(qint64  Recv,qint64 all)

    ui->progressBar->setMaximum(all);

    ui->progressBar->setValue(Recv);

进度条初始化

   ui->progressBar->setValue(0);

    ui->progressBar->setMinimum(0);