Qt 讀寫XML文件

#ifndef SIM_XMLSTREAMREADER_H_
#define SIM_XMLSTREAMREADER_H_

#include <QString>
#include <QXmlStreamReader>

class XmlStreamReader
{
public:
    XmlStreamReader();
    ~XmlStreamReader();
    //讀取文件
    bool ReadFile(const QString &fileName);
    
    //跳過不能識別的元素
    void SkipUnknownElement();

    //讀取XML文件的主體部分
    void ReadWantDecideEditElement();

    //解析想定基本信息
    void ReadScenarioElement();

    //解析想定文件實體信息
    void ReadEntitiesElement();

    //解析想定文件模型發布訂閱關系
    void ReadModelsElement();


    //解析該實體的所有參數
    void ReadParametersElement();

    //解析發布關系
    void ReadPublishElement();

    //解析訂閱關系
    void ReadSubscribeElement();

private:
    QXmlStreamReader m_qxml_reader;
};

#endif //SIM_XMLSTREAMREADER_H_

#include "xml_stream_reader.h"
#include <QFile>
#include <QDebug>
#include <iostream>
using namespace std;



XmlStreamReader::XmlStreamReader()
{

}


XmlStreamReader::~XmlStreamReader()
{
}

bool XmlStreamReader::ReadFile(const QString &fileName)
{
    QFile file(fileName);
    if (!file.open(QFile::ReadOnly | QFile::Text)) 
    {
        std::cerr << "Error: Cannot read file " << qPrintable(fileName)<< ": " << qPrintable(file.errorString())<< std::endl;
        return false;
    }
    //如果文件打開成功，將它設置為QXmlStreamReader的輸入設備
    m_qxml_reader.setDevice(&file);

    //readNext()函數從輸入流中讀取下一個記號，如果成功而且還沒有到達XML文件的結尾，函數將進入while循環，
    //每次調用readNext()函數，下一個記號就會被讀取並變成當前的記號，readNext()函數報告error，atEnd返回true
    m_qxml_reader.readNext(); 
    //當讀取到XML文檔結尾，或者發生錯誤，atEnd()函數返回true
    while (!m_qxml_reader.atEnd()) 
    {
        //如果當前記號為StartElement，返回true
        if (m_qxml_reader.isStartElement())
        {
            if (m_qxml_reader.name() == "WantDecideEdit") 
            {
                ReadWantDecideEditElement();
            }
            else 
            {
                m_qxml_reader.raiseError(QObject::tr("Not a WantDecideEdit file"));
            }
        }
        else 
        {
            m_qxml_reader.readNext();
        }
    }

    file.close();
    if (m_qxml_reader.hasError())
    {
        std::cerr << "Error: Failed to parse file "<< qPrintable(fileName) << ": "<< qPrintable(m_qxml_reader.errorString()) << std::endl;
        return false;
    }
    else if (file.error() != QFile::NoError) 
    {
        std::cerr << "Error: Cannot read file " << qPrintable(fileName)<< ": " << qPrintable(file.errorString())<< std::endl;
        return false;
    }
    return true;
}

void XmlStreamReader::ReadWantDecideEditElement()
{
    //跳過當前記號，只可能是WantDecideEdit記號
    m_qxml_reader.readNext();
    while (!m_qxml_reader.atEnd()) 
    {
        //如果讀取到關閉標簽，只能是</WantDecideEdit>記號，跳過這個標簽並跳出循環
        if (m_qxml_reader.isEndElement())
        {
            if (m_qxml_reader.name() == "WantDecideEdit")
            {
                m_qxml_reader.readNext();
                break;
            }
            else
                m_qxml_reader.readNext();
        }

        if (m_qxml_reader.isStartElement())
        {
            if (m_qxml_reader.name() == "ScenarioInfo")
            {
                ReadScenarioElement();
            }
            else if (m_qxml_reader.name() == "Entities")
            {
                ReadEntitiesElement();
            }
            else if (m_qxml_reader.name() == "Models")
            {
                ReadModelsElement();
            }
            else
            {
                SkipUnknownElement();
            }
        }
        else
        {
            m_qxml_reader.readNext();
        }
    }
}


void XmlStreamReader::ReadScenarioElement()
{
    m_qxml_reader.readNext();
    while (!m_qxml_reader.atEnd()) 
    {
        if (m_qxml_reader.isEndElement()) 
        {
            if (m_qxml_reader.name() == "ScenarioInfo")
            {
                m_qxml_reader.readNext();
                break;
            }
            else
                m_qxml_reader.readNext();
        }

        if (m_qxml_reader.isStartElement()) 
        {
            if (m_qxml_reader.name() == "Name")
            {
                QString name = m_qxml_reader.readElementText();
                qDebug() << "name:" << name << endl;
            }
            else if (m_qxml_reader.name() == "ModificationDate")
            {
                
                QString modification_date = m_qxml_reader.readElementText();
                qDebug() << "modification_date:" << modification_date << endl;

            }
            else if (m_qxml_reader.name() == "Description")
            {
                QString description = m_qxml_reader.readElementText();
                qDebug() << "description:" << description << endl;
                return;

            }
            else 
            {
                SkipUnknownElement();
            }
        }
        else 
        {
            m_qxml_reader.readNext();
        }
    }
}

void XmlStreamReader::ReadParametersElement()
{
    m_qxml_reader.readNext();
    while (!m_qxml_reader.atEnd())
    {
        if (m_qxml_reader.isEndElement())
        {
            if (m_qxml_reader.name() == "Parameters")
            {
                m_qxml_reader.readNext();
                break;
            }
            else
                m_qxml_reader.readNext();
        }

        if (m_qxml_reader.isStartElement())
        {
            if (m_qxml_reader.name() == "Parameter")
            {
                QString name = m_qxml_reader.attributes().value("name").toString();
                QString type = m_qxml_reader.attributes().value("type").toString();
                QString display_name = m_qxml_reader.attributes().value("displayName").toString();
                QString usage = m_qxml_reader.attributes().value("usage").toString();
                QString value = m_qxml_reader.attributes().value("value").toString();
                qDebug() << "name:" << name << " " << "type:" << type << " " << "display_name:" << display_name << " " << "usage:" << usage << " " << "value:" << value << endl;
                m_qxml_reader.readNext();
            }
            else
            {
                SkipUnknownElement();
            }
        }
        else
        {
            m_qxml_reader.readNext();
        }
    }
}

void XmlStreamReader::ReadPublishElement()
{
    m_qxml_reader.readNext();
    while (!m_qxml_reader.atEnd())
    {
        if (m_qxml_reader.isEndElement())
        {
            if (m_qxml_reader.name() == "Publish")
            {
                m_qxml_reader.readNext();
                break;
            }
            else
                m_qxml_reader.readNext();
        }

        if (m_qxml_reader.isStartElement())
        {
            if (m_qxml_reader.name() == "Topic")
            {
                QString topic_name = m_qxml_reader.attributes().value("topicName").toString();
                QString topic_param_name = m_qxml_reader.attributes().value("topicParamName").toString();
                QString model_param_name = m_qxml_reader.attributes().value("modelParamName").toString();
                qDebug() << "topicName:" << topic_name << ",topicParamName:" << topic_param_name << ",modelParamName:" << model_param_name << endl;
                m_qxml_reader.readNext();
            }
            else
            {
                SkipUnknownElement();
            }
        }
        else
        {
            m_qxml_reader.readNext();
        }
    }
}

void XmlStreamReader::ReadSubscribeElement()
{
    m_qxml_reader.readNext();
    while (!m_qxml_reader.atEnd())
    {
        if (m_qxml_reader.isEndElement())
        {
            if (m_qxml_reader.name() == "Subscribe")
            {
                m_qxml_reader.readNext();
                break;
            }
            else
                m_qxml_reader.readNext();
        }

        if (m_qxml_reader.isStartElement())
        {
            if (m_qxml_reader.name() == "Topic")
            {
                QString topic_name = m_qxml_reader.attributes().value("topicName").toString();
                QString topic_param_name = m_qxml_reader.attributes().value("topicParamName").toString();
                QString model_param_name = m_qxml_reader.attributes().value("modelParamName").toString();
                qDebug() << "topicName:" << topic_name << ",topicParamName:" << topic_param_name << ",modelParamName:" << model_param_name << endl;
                m_qxml_reader.readNext();
            }
            else
            {
                SkipUnknownElement();
            }
        }
        else
        {
            m_qxml_reader.readNext();
        }
    }
}

void XmlStreamReader::ReadEntitiesElement()
{
    m_qxml_reader.readNext();
    while (!m_qxml_reader.atEnd()) 
    {
        if (m_qxml_reader.isEndElement()) 
        {
            if (m_qxml_reader.name() == "Entities")
            {
                m_qxml_reader.readNext();
                break;
            }
            else
                m_qxml_reader.readNext();
        }

        if (m_qxml_reader.isStartElement()) 
        {
            if (m_qxml_reader.name() == "Entity")
            {
                QString object_handle = m_qxml_reader.attributes().value("objectHandle").toString();
                qDebug() << "objectHandle:" << object_handle << endl;
                QString model_uuid = m_qxml_reader.attributes().value("modelUUID").toString();
                qDebug() << "modelUUID:" << model_uuid<<endl;
                m_qxml_reader.readNext();
            }
            else if (m_qxml_reader.name() == "Parameters")
            {
                ReadParametersElement();
            }
            else 
            {
                SkipUnknownElement();
            }
        }
        else 
        {
            m_qxml_reader.readNext();
        }
    }
}

void XmlStreamReader::ReadModelsElement()
{
    m_qxml_reader.readNext();
    while (!m_qxml_reader.atEnd()) 
    {
        if (m_qxml_reader.isEndElement()) 
        {
            if (m_qxml_reader.name() == "Models")
            {
                m_qxml_reader.readNext();
                break;
            }
            else
                m_qxml_reader.readNext();
        }

        if (m_qxml_reader.isStartElement()) 
        {
            if (m_qxml_reader.name() == "Model")
            {
                QString model_uuid = m_qxml_reader.attributes().value("modelUUID").toString();
                qDebug() << "modelUUID:" << model_uuid<<endl;
                m_qxml_reader.readNext();
            }
            else if (m_qxml_reader.name() == "Publish")
            {
                ReadPublishElement();
            }
            else if (m_qxml_reader.name() == "Subscribe")
            {
                ReadSubscribeElement();
            }
            else 
            {
                SkipUnknownElement();
            }
        }
        else 
        {
            m_qxml_reader.readNext();
        }
    }
}
void XmlStreamReader::SkipUnknownElement()
{
    m_qxml_reader.readNext();
    while (!m_qxml_reader.atEnd()) 
    {
        if (m_qxml_reader.isEndElement()) 
        {
            m_qxml_reader.readNext();
            break;
        }

        if (m_qxml_reader.isStartElement()) 
        {
            SkipUnknownElement();
        }
        else 
        {
            m_qxml_reader.readNext();
        }
    }
}

void writeIndexEntry(QXmlStreamWriter *xmlWriter, QTreeWidgetItem *item)
{
    xmlWriter->writeStartElement("entry");
    xmlWriter->writeAttribute("term", item->text(0));
    QString pageString = item->text(1);
    if (!pageString.isEmpty())
    {
        QStringList pages = pageString.split(", ");
        foreach(QString page, pages)
            xmlWriter->writeTextElement("page", page);
    }
    for (int i = 0; i < item->childCount(); ++i)
        writeIndexEntry(xmlWriter, item->child(i));
    xmlWriter->writeEndElement();
}


bool WriteXml(const QString &fileName, QTreeWidget *treeWidget)
{
    QFile file(fileName);
    if (!file.open(QFile::WriteOnly | QFile::Text)) 
    {
        std::cerr << "Error: Cannot write file "<< qPrintable(fileName) << ": "<< qPrintable(file.errorString()) << std::endl;
        return false;
    }

    QXmlStreamWriter xmlWriter(&file);
    //開啟自動格式編輯功能，XML文檔將以更友好易讀的格式輸出，在每一行都有明確顯示數據遞歸結構的縮進
    xmlWriter.setAutoFormatting(true);
    //在XML文檔首行寫"<?xml version="1.0" encoding="UTF-8"?>"
    xmlWriter.writeStartDocument();
    xmlWriter.writeStartElement("WantDecideEdit");
    for (int i = 0; i < treeWidget->topLevelItemCount(); ++i)
        writeIndexEntry(&xmlWriter, treeWidget->topLevelItem(i));
    xmlWriter.writeEndDocument();

    file.close();
    if (file.error())
    {
        std::cerr << "Error: Cannot write file "<< qPrintable(fileName) << ": "<< qPrintable(file.errorString()) << std::endl;
        return false;
    }
    return true;
}