文章目录
前言一、XML文件二、INI文件三、JSON文件四、示例代码及文件内容五、下载链接总结前言
在项目开发过程中，发现经常遇见一些比如XML、INI、JSON等文件的读写，这里对这些文件进行整理和汇总，并展示一个简单的demo来实现上述文件的读写，以便大家学习，如有错误之处，欢迎大家批评指正。
项目效果
提示：以下是本篇文章正文内容，下面案例可供参考
一、XML文件
XML是可扩展标记语言，是一种通用的文本格式，被广泛运用于数据交换和数据存储，也可以用作配置文件。
在Qt中有三种方式来进行xml文件的读取：
1.使用XML流，读：QXmlStreamReader 写：QXmlStreamWriter
2.使用DOM读写
3.SAX为XML解析器提供了一个基于事件的标准接口
其中本文示例中使用的是第一种方式来进行读写，需要包含以下头文件，具体实现方式可看下文完整代码
//xml#include <QFile>#include <QXmlStreamReader>#include <QXmlStreamWriter>
二、INI文件
INI文件即初始化文件，通常存放的是一个程序的初始化信息，常用来做配置文件，其结构比较简单，由节、键、值组成，比较容易操作。
在Qt中可以使用QSettings类来进行ini文件的读写，需要包含以下头文件，具体实现方式可看下文完整代码
//ini#include <QSettings>
三、JSON文件
JSON是一种轻量级的数据交换格式，它基于JavaScript的一个子集，易于人的编写和阅读，也易于机器解析，json 文件由对象和数组组成。
本文的demo中读写的json文件比较简单，只有对象，但是在使用到数组的情况下需要包含以下头文件，具体实现方式可看下文完整代码
//json#include <QJsonObject> //对象#include <QJsonArray> //数组#include <QJsonDocument>
四、示例代码及文件内容
1.widget.h
#ifndef WIDGET_H#define WIDGET_H#include <QWidget>#include <QMessageBox>#include <QDebug>//xml#include <QFile>#include <QXmlStreamReader>#include <QXmlStreamWriter>//ini#include <QSettings>//json#include <QJsonObject>#include <QJsonDocument>QT_BEGIN_NAMESPACEnamespace Ui {class Widget; }QT_END_NAMESPACEtypedef struct person{QString name;QString gender;int age;double height;double weight;}PersonData;class Widget : public QWidget{Q_OBJECTpublic:Widget(QWidget *parent = nullptr);~Widget();void xmlFlieRead();bool xmlFileWrite();void iniFileRead();bool iniFileWrite();void jsonFileRead();bool jsonFileWrite();void setFileValue(QString fileType);void showFileValue(QString fileType);private slots:void on_pb_xmlRead_clicked();void on_pb_xmlWrite_clicked();void on_pb_iniRead_clicked();void on_pb_iniWrite_clicked();void on_pb_jsonRead_clicked();void on_pb_jsonWrite_clicked();private:Ui::Widget *ui;PersonData xmlData;PersonData iniData;PersonData jsonData;};#endif // WIDGET_H
2.widget.cpp
#include "widget.h"#include "ui_widget.h"Widget::Widget(QWidget *parent): QWidget(parent), ui(new Ui::Widget){ui->setupUi(this);this->xmlFlieRead(); //初始化读取xml文件}Widget::~Widget(){delete ui;}void Widget::xmlFlieRead(){QString xmlFile = "D:/QT/Project/my_Project/18_FileReadWrite/TestFile/xmlFile.xml";QFile file(xmlFile);if(!file.open(QFile::ReadOnly | QFile::Text)){QMessageBox::warning(this,"警告","xml文件打开失败!");return;}QXmlStreamReader xmlRead;xmlRead.setDevice(&file);if(xmlRead.readNextStartElement()) //读取root{if(xmlRead.name().toString() == "root"){if(xmlRead.readNextStartElement()) //读取config{if(xmlRead.name().toString() == "config"){while(xmlRead.readNextStartElement()) //循环读取Item{if(xmlRead.name().toString() == "Item"){QXmlStreamAttributes attributes = xmlRead.attributes();if(attributes.hasAttribute("Name")){QString s_name = attributes.value("Name").toString();//qDebug()<<"s_name:"<<s_name;if(s_name == "name"){xmlData.name = xmlRead.readElementText();}else if(s_name == "gender"){xmlData.gender = xmlRead.readElementText();}else if(s_name == "age"){xmlData.age = xmlRead.readElementText().toInt();}else if(s_name == "height"){xmlData.height = xmlRead.readElementText().toDouble();}else if(s_name == "weight"){xmlData.weight = xmlRead.readElementText().toDouble();}else{qDebug()<<"readItem error";xmlRead.readNextStartElement();}}}}}}}}//更新界面showFileValue("xml");}bool Widget::xmlFileWrite(){QString xmlFile = "D:/QT/Project/my_Project/18_FileReadWrite/TestFile/xmlFile.xml";QFile file(xmlFile);if(!file.open(QFile::WriteOnly | QFile::Text | QFile :: Truncate)){return false;}QXmlStreamWriter xmlWrite(&file);xmlWrite.setAutoFormatting(true);xmlWrite.writeStartDocument("1.0",true);xmlWrite.writeStartElement("root");xmlWrite.writeStartElement("config");xmlWrite.writeAttribute("filename","xmlFile.xml");xmlWrite.writeStartElement ("Item");xmlWrite.writeAttribute("Name","name");xmlWrite.writeAttribute("Type","string");xmlWrite.writeAttribute("Note","姓名");xmlWrite.writeCharacters(xmlData.name);xmlWrite.writeEndElement();xmlWrite.writeStartElement ("Item");xmlWrite.writeAttribute("Name","gender");xmlWrite.writeAttribute("Type","string");xmlWrite.writeAttribute("Note","性别");xmlWrite.writeCharacters(xmlData.gender);xmlWrite.writeEndElement();xmlWrite.writeStartElement ("Item");xmlWrite.writeAttribute("Name","age");xmlWrite.writeAttribute("Type","int");xmlWrite.writeAttribute("Note","年龄");xmlWrite.writeCharacters(QString::number(xmlData.age));xmlWrite.writeEndElement();xmlWrite.writeStartElement ("Item");xmlWrite.writeAttribute("Name","height");xmlWrite.writeAttribute("Type","double");xmlWrite.writeAttribute("Note","身高");xmlWrite.writeCharacters(QString::number(xmlData.height));xmlWrite.writeEndElement();xmlWrite.writeStartElement ("Item");xmlWrite.writeAttribute("Name","weight");xmlWrite.writeAttribute("Type","double");xmlWrite.writeAttribute("Note","体重");xmlWrite.writeCharacters(QString::number(xmlData.weight));xmlWrite.writeEndElement();xmlWrite.writeEndElement(); //config结束xmlWrite.writeEndElement(); //root结束xmlWrite.writeEndDocument(); //Document结束file.close();return true;}void Widget::iniFileRead(){QString iniFile = "D:/QT/Project/my_Project/18_FileReadWrite/TestFile/iniFile.ini";QSettings iniRead(iniFile,QSettings::IniFormat);iniRead.setIniCodec("UTF-8"); //注意编码iniRead.beginGroup("VALUE");iniData.name = iniRead.value("name").toString();iniData.gender = iniRead.value("gender").toString();iniData.age = iniRead.value("age").toInt();iniData.height = iniRead.value("height").toDouble();iniData.weight = iniRead.value("weight").toDouble();iniRead.endGroup();//更新界面showFileValue("ini");}bool Widget::iniFileWrite(){QString iniFile = "D:/QT/Project/my_Project/18_FileReadWrite/TestFile/iniFile.ini";QSettings iniWrite(iniFile,QSettings::IniFormat);iniWrite.setIniCodec("UTF-8"); //注意编码,解决中文字符乱码iniWrite.beginGroup("VALUE");iniWrite.setValue("name",iniData.name);iniWrite.setValue("gender",iniData.gender);iniWrite.setValue("age",iniData.age);iniWrite.setValue("height",iniData.height);iniWrite.setValue("weight",iniData.weight);iniWrite.endGroup();return true;}void Widget::jsonFileRead(){QString jsonFile = "D:/QT/Project/my_Project/18_FileReadWrite/TestFile/jsonFile.json";QFile file(jsonFile);if(!file.open(QIODevice::ReadOnly)){QMessageBox::warning(this,"警告","json文件打开失败!");return;}QByteArray data(file.readAll());file.close();QJsonParseError jError;QJsonDocument jDoc = QJsonDocument::fromJson(data,&jError);if(jError.error != QJsonParseError::NoError){QMessageBox::critical(this,"错误","json文件错误!");return;}QJsonObject mainObject = jDoc.object();{jsonData.name = mainObject["name"].toString();jsonData.gender = mainObject["gender"].toString();jsonData.age = mainObject["age"].toInt();jsonData.height = mainObject["height"].toDouble();jsonData.weight = mainObject["weight"].toDouble();}//更新界面showFileValue("json");}bool Widget::jsonFileWrite(){QJsonObject mainObject; //读写比较复杂的json文件,可以使用大括号来方便区分{mainObject.insert("name",jsonData.name);mainObject.insert("gender",jsonData.gender);mainObject.insert("age",jsonData.age);mainObject.insert("height",jsonData.height);mainObject.insert("weight",jsonData.weight);}QJsonDocument jDoc(mainObject);QString jsonFile = "D:/QT/Project/my_Project/18_FileReadWrite/TestFile/jsonFile.json";QFile file(jsonFile);if(!file.open(QIODevice::WriteOnly)){return false;}QByteArray data(jDoc.toJson());file.write(data);file.close();return true;}void Widget::setFileValue(QString fileType){if(fileType == "xml"){xmlData.name = ui->le_name->text();xmlData.gender = ui->cb_gender->currentText();xmlData.age = ui->le_age->text().toInt();xmlData.height = ui->le_height->text().toDouble();xmlData.weight = ui->le_weight->text().toDouble();}else if(fileType == "ini"){iniData.name = ui->le_name->text();iniData.gender = ui->cb_gender->currentText();iniData.age = ui->le_age->text().toInt();iniData.height = ui->le_height->text().toDouble();iniData.weight = ui->le_weight->text().toDouble();}else if(fileType == "json"){jsonData.name = ui->le_name->text();jsonData.gender = ui->cb_gender->currentText();jsonData.age = ui->le_age->text().toInt();jsonData.height = ui->le_height->text().toDouble();jsonData.weight = ui->le_weight->text().toDouble();}}void Widget::showFileValue(QString fileType){if(fileType == "xml"){ui->le_name->setText(xmlData.name);if(xmlData.gender == "男"){ui->cb_gender->setCurrentIndex(0);}else if(xmlData.gender == "女"){ui->cb_gender->setCurrentIndex(1);}else{ui->cb_gender->setCurrentIndex(0);}ui->le_age->setText(QString::number(xmlData.age));ui->le_height->setText(QString::number(xmlData.height));ui->le_weight->setText(QString::number(xmlData.weight));}else if(fileType == "ini"){ui->le_name->setText(iniData.name);if(iniData.gender == "男"){ui->cb_gender->setCurrentIndex(0);}else{ui->cb_gender->setCurrentIndex(1);}ui->le_age->setText(QString::number(iniData.age));ui->le_height->setText(QString::number(iniData.height));ui->le_weight->setText(QString::number(iniData.weight));}else if(fileType == "json"){ui->le_name->setText(jsonData.name);if(jsonData.gender == "男"){ui->cb_gender->setCurrentIndex(0);}else{ui->cb_gender->setCurrentIndex(1);}ui->le_age->setText(QString::number(jsonData.age));ui->le_height->setText(QString::number(jsonData.height));ui->le_weight->setText(QString::number(jsonData.weight));}}void Widget::on_pb_xmlRead_clicked(){xmlFlieRead();}void Widget::on_pb_xmlWrite_clicked(){setFileValue("xml");if(xmlFileWrite()){QMessageBox::information(this,"提示","xml文件保存成功!");}}void Widget::on_pb_iniRead_clicked(){iniFileRead();}void Widget::on_pb_iniWrite_clicked(){setFileValue("ini");if(iniFileWrite()){QMessageBox::information(this,"提示","ini文件保存成功!");}}void Widget::on_pb_jsonRead_clicked(){jsonFileRead();}void Widget::on_pb_jsonWrite_clicked(){setFileValue("json");if(jsonFileWrite()){QMessageBox::information(this,"提示","json文件保存成功!");}}
3.widget.ui
4.示例中各文件的内容
五、下载链接
我的示例百度网盘链接：/s/1M1Flq0-1lj4A5KV3sRdLUw
提取码：xxcj
总结
可以看到本文demo中所进行读写的几个文件都是比较简单的，内容比较少并且结构也比较简易，这里也只是为大家展示基本的读写方法。但是在实际的开发过程中，文件内容会存在循环，嵌套等等的复杂结构，对于相关的文件大家可以查看文末的参考文章。在我们的开发过程中需要注意观察，其实这几种类型的文件读写都是比较简单的，本质上都是获取参数，进行文件写，读取参数，界面显示读到的参数。另外在实际开发中，建议先进行写文件，再然后读，这样感觉开发起来简单（哈哈这是我自己的感jio~~~）。
hello：
共同学习，共同进步，如果还有相关问题，可在评论区留言进行讨论。
参考文章：
QT中读取XML文件三种方式的实例
Qt读写ini文件
JSON简介
Qt 操作Json格式文件（创建、插入、解析、修改、删除）
