QT如何实现调用打印机来打印html中的网页及文件

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QTableWidget>
#include <QPainter>
#include <QtPrintSupport/QPrinter>
#include <QtPrintSupport/QPrintDialog>
#include <QFileInfo>
#include <windows.h>
#include <QFileDialog>
#include <QtPrintSupport/QPrintPreviewDialog>
#include <QtPrintSupport/QPageSetupDialog>
#include <fstream>
#include <iostream>
#include <sstream>
#include <QWebView>
namespace Ui {
class Widget;
}
class Widget : public QWidget
{
 Q_OBJECT
public: 
 explicit Widget(QWidget *parent = 0);
 ~Widget();
 
private slots:
 void on_pushButton_clicked(); 
 void printPreview(QPrinter *printer);
private:
 Ui::Widget *ui; 
 void doPrint(); 
 void doPrintPreview(); 
 void createPdf(); 
 void setUpPage(); 
 bool printFile(const QString & filePath);

};

#include "Widget.h"
#include "ui_Widget.h"

Widget::Widget(QWidget *parent) :
 QWidget(parent),
 ui(new Ui::Widget)
{
 ui->setupUi(this); //这里没用QFile文件读html文件，因为会使html网页中文成乱码
 QString strHtmltext; 
 std::string bufStr; 
 std::ifstream readFile;
 readFile.open("D:\\qqq.html"); 
 if(readFile.is_open())
 { 
 while(getline(readFile, bufStr))
 {
 strHtmltext += QString(bufStr.data());
 }
 readFile.close();
 }
 ui->webView->setHtml(strHtmltext);

}

Widget::~Widget()
{ delete ui;
}//点击这里触发打印动作！
void Widget::on_pushButton_clicked()
{

 doPrint();
// doPrintPreview();
// printFile("D:/123.txt");
}

void Widget::doPrint()
{ 
 // 创建打印机对象
 QPrinter printer; 
 // 创建打印对话框
 QString printerName = printer.printerName(); 
 if( printerName.size() == 0) 
 return;
 QPrintDialog dlg(&printer, this);#if 0
 //如果编辑器中有选中区域，则打印选中区域
 if (ui->textEdit->textCursor().hasSelection())
 dlg.addEnabledOption(QAbstractPrintDialog::PrintSelection);
#endif
 // 如果在对话框中按下了打印按钮，则执行打印操作
// if (dlg.exec() == QDialog::Accepted)
 //这里使用默认打印机，不用每次选择打印机
 {
// ui->textEdit->print(&printer);
 ui->webView->print(&printer); 
 
 // print the existing document by absoult path
 // printFile("D:/myRSM.doc");
 }
}
// 打印预览void Widget::doPrintPreview()
{
 QPrinter printer; 
 // 创建打印预览对话框
 QPrintPreviewDialog preview(&printer, this); 
 // 当要生成预览页面时，发射paintRequested()信号
 connect(&preview, SIGNAL(paintRequested(QPrinter*)),this,SLOT(printPreview(QPrinter*)));
 preview.exec();
}

void Widget::printPreview(QPrinter *printer)
{
// ui->textEdit->print(printer);
 ui->webView->print(printer);
}

// 生成PDF文件
void Widget::createPdf()
{
 QString fileName = QFileDialog::getSaveFileName(this, tr("导出PDF文件"), QString(), "*.pdf"); 
 if (!fileName.isEmpty()) { 
 // 如果文件后缀为空，则默认使用.pdf
 if (QFileInfo(fileName).suffix().isEmpty())
 fileName.append(".pdf");
 QPrinter printer; 
 // 指定