Qt 读写XML文件

#ifndef SIM_XMLSTREAMREADER_H_
#define SIM_XMLSTREAMREADER_H_

#include <QString>
#include <QXmlStreamReader>

class XmlStreamReader
{
public:
    XmlStreamReader();
    ~XmlStreamReader();
    //读取文件
    bool ReadFile(const QString &fileName);
    
    //跳过不能识别的元素
    void SkipUnknownElement();

    //读取XML文件的主体部分
    void ReadWantDecideEditElement();

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

    //解析想定文件实体信息
    void ReadEntitiesElement();

    //解析想定文件模型发布订阅关系
    void ReadModelsElement();


    //解析该实体的所有参数
    void ReadParametersElement();

    //解析发布关系
    void ReadPublishElement();

    //解析订阅关系
    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;
    }
    //如果文件打开成功，将它设置为QXmlStreamReader的输入设备
    m_qxml_reader.setDevice(&file);

    //readNext()函数从输入流中读取下一个记号，如果成功而且还没有到达XML文件的结尾，函数将进入while循环，
    //每次调用readNext()函数，下一个记号就会被读取并变成当前的记号，readNext()函数报告error，atEnd返回true
    m_qxml_reader.readNext(); 
    //当读取到XML文档结尾，或者发生错误，atEnd()函数返回true
    while (!m_qxml_reader.atEnd()) 
    {
        //如果当前记号为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()
{
    //跳过当前记号，只可能是WantDecideEdit记号
    m_qxml_reader.readNext();
    while (!m_qxml_reader.atEnd()) 
    {
        //如果读取到关闭标签，只能是</WantDecideEdit>记号，跳过这个标签并跳出循环
        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);
    //开启自动格式编辑功能，XML文档将以更友好易读的格式输出，在每一行都有明确显示数据递归结构的缩进
    xmlWriter.setAutoFormatting(true);
    //在XML文档首行写"<?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;
}