40.DOM读取XML

main.cpp

#include <QtGui>
#include <iostream>

#include "domparser.h"

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QDir::setCurrent(app.applicationDirPath());//设置路径为当前目录


    QStringList labels;
    labels << QObject::tr("Terms") << QObject::tr("Pages");

    QTreeWidget treeWidget;
    treeWidget.setHeaderLabels(labels);
    treeWidget.header()->setResizeMode(QHeaderView::Stretch);
    treeWidget.setWindowTitle(QObject::tr("DOM Parser"));
    treeWidget.show();

    DomParser parser(&treeWidget);
    parser.readFile("in1.xml");

    return app.exec();
}

DomPaser.h

#ifndef DOMPARSER_H
#define DOMPARSER_H

class QDomElement;
class QString;
class QTreeWidget;
class QTreeWidgetItem;

class DomParser
{
public:
    DomParser(QTreeWidget *tree);
    //打开传递来的文件
    bool readFile(const QString &fileName);

private:
    void parseBookindexElement(const QDomElement &element);
    void parseEntryElement(const QDomElement &element,
                           QTreeWidgetItem *parent);
    void parsePageElement(const QDomElement &element,
                          QTreeWidgetItem *parent);

    QTreeWidget *treeWidget;
};

#endif

domparser.cpp

#include <QtGui>
#include <QtXml>
#include <iostream>

#include "domparser.h"

DomParser::DomParser(QTreeWidget *tree)
{
    treeWidget = tree;
}

//读文件
bool DomParser::readFile(const QString &fileName)
{
    QFile file(fileName);
    //判断是否打开成功
    if (!file.open(QFile::ReadOnly | QFile::Text)) {
        std::cerr << "Error: Cannot read file " << qPrintable(fileName)
                  << ": " << qPrintable(file.errorString())
                  << std::endl;
        return false;
    }

    //错误信息
    QString errorStr;
    //错误行
    int errorLine;
    //错误项
    int errorColumn;

    QDomDocument doc;
    //setContent解析XML文档,如果文档没打开,
    //setContent将自动打开,false参数将禁用命名空间的处理.
    if (!doc.setContent(&file, false, &errorStr, &errorLine,
                        &errorColumn)) {
        std::cerr << "Error: Parse error at line " << errorLine << ", "
                  << "column " << errorColumn << ": "
                  << qPrintable(errorStr) << std::endl;
        return false;
    }

    //如果解析成功,就对QDomDocument调用documentElement获取它唯一的
    //QDomElement子对象
    QDomElement root = doc.documentElement();
    //判断是否有<bookindex>元素,如果有就调用QDomElement来解析
    if (root.tagName() != "bookindex") {
        std::cerr << "Error: Not a bookindex file" << std::endl;
        return false;
    }

    parseBookindexElement(root);
    return true;
}

//遍历所有子节点
void DomParser::parseBookindexElement(const QDomElement &element)
{
    //发现下一个子对象
    QDomNode child = element.firstChild();
    //如果不为空
    while (!child.isNull()) {
        if (child.toElement().tagName() == "entry")
        {
            parseEntryElement(child.toElement(),
                              treeWidget->invisibleRootItem());
        }
        child = child.nextSibling();
    }
}

//entry标签处理
void DomParser::parseEntryElement(const QDomElement &element,
                                  QTreeWidgetItem *parent)
{
    QTreeWidgetItem *item = new QTreeWidgetItem(parent);
    item->setText(0, element.attribute("term"));

    QDomNode child = element.firstChild();
    while (!child.isNull()) 
    {
        //如果是entry调用entry处理
        if (child.toElement().tagName() == "entry") 
        {
            parseEntryElement(child.toElement(), item);
        }
        //如果是page调用page处理
        else if (child.toElement().tagName() == "page") 
        {
            parsePageElement(child.toElement(), item);
        }
        //继续处理下一个
        child = child.nextSibling();
    }
}

//处理page项
void DomParser::parsePageElement(const QDomElement &element,
                                 QTreeWidgetItem *parent)
{
    QString page = element.text();
    QString allPages = parent->text(1);
    if (!allPages.isEmpty())
        allPages += ", ";
    allPages += page;
    parent->setText(1, allPages);
}