QXmlStreamReader读取空文本，文档肯定不是空的

QXmlStreamReader reads empty text, document is for sure not empty

本文关键字：文档 读取 文本 QXmlStreamReader      更新时间：2023-10-16

我在应用程序中使用QXmlStreamReader和QXmlStreamWriter读取和写入XML文件。

我的示例XML文件如下所示：

<?xml version="1.0" encoding="UTF-8"?>
<Senders>
    <Sender>
        <Name>COMPANY XYZ</Name>
        <Street>Random</Street>
        <BuildingNumber>23D</BuildingNumber>
        <LocalNumber>123</LocalNumber>
        <CityCode>3434-21</CityCode>
        <City>New York</City>
    </Sender>
</Senders>

它是用我的代码写的。基本上，我在编写XML文件时没有问题，但在编写后尝试读取它们时会遇到一些问题。这是我的代码，它打印出空值（XML文件不是空的）。

#include "mainwindow.h"
#include <QApplication>
#include <QtCore>
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QFile file("../data.xml");
    if(file.open(QIODevice::WriteOnly | QIODevice::Text))
    {
        QXmlStreamWriter xmlWriter(&file);
        xmlWriter.setAutoFormatting(true);
        xmlWriter.writeStartDocument();
        xmlWriter.writeStartElement("Senders");
        xmlWriter.writeStartElement("Sender");
        xmlWriter.writeTextElement("Name", "COMPANY XYZ");
        xmlWriter.writeTextElement("Street", "Random");
        xmlWriter.writeTextElement("BuildingNumber", "23D");
        xmlWriter.writeTextElement("LocalNumber", "123");
        xmlWriter.writeTextElement("CityCode", "3434-21");
        xmlWriter.writeTextElement("City", "New York");
        xmlWriter.writeEndElement();
        xmlWriter.writeEndElement();
        file.close();
    }
    QVector<QString> data;
    if(file.open(QIODevice::ReadOnly | QIODevice::Text))
    {
        QXmlStreamReader xmlReader(&file);
        while (!xmlReader.atEnd() && !xmlReader.hasError())
        {
            xmlReader.readNext();
            if (xmlReader.isStartElement())
            {
                qDebug() << "element name: '" << xmlReader.name().toString() << "'"
                         << ", text: '" << xmlReader.text().toString() << "'" << endl;
            }
        }
        file.close();
    }
    return a.exec();
}

那么，我在阅读文件时做错了什么？

我得到的输出：

element name: ' "Senders" ' , text: ' "" ' 
element name: ' "Sender" ' , text: ' "" ' 
element name: ' "Name" ' , text: ' "" ' 
element name: ' "Street" ' , text: ' "" ' 
element name: ' "BuildingNumber" ' , text: ' "" ' 
element name: ' "LocalNumber" ' , text: ' "" ' 
element name: ' "CityCode" ' , text: ' "" ' 
element name: ' "City" ' , text: ' "" '

当您使用StartElement令牌时，您只能获取此元素的名称，而不能获取其值。您需要进一步阅读并获得Characters令牌才能读取元素的值。您还希望跳过仅限空白的标记：

while (!xmlReader.atEnd() && !xmlReader.hasError())
{
    xmlReader.readNext();
    //here we are at StartElement, so we can read the element's name
    if (xmlReader.isStartElement())
    {
        qDebug() << "element name: '" << xmlReader.name().toString() << "'";
    }
    //here we are inside the element, so if it is not empty, we can read the element's value
    else if(xmlReader.isCharacters() && !xmlReader.isWhitespace())
    {
        qDebug() << "element value: '" <<xmlReader.text().toString() << "'";
    }
}
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