Qt操作xml文件（增删改功能）

来源：互联网发布：麻瓜编程python 编辑：程序博客网时间：2024/04/29 15:50

这个例子是在根据网上博客《Qt数据库（XML）》改写的一个操作XML的实现。

借鉴了很多里面的代码，大家可以结合上面的博客对照，相信你肯定会对XML的操作熟练起来。

我建立的是Qwidget项目，没有添加ui文件，输出内容都放在应用程序输出中（qDebug）。

XMLtest.pro文件代码：

#-------------------------------------------------## Project created by QtCreator 2012-08-15T15:56:54##-------------------------------------------------QT       += core gui xmlTARGET = XMLtestTEMPLATE = appSOURCES += main.cpp\        widget.cppHEADERS  += widget.h

widget.h文件代码：

#ifndef WIDGET_H#define WIDGET_H#include <QtGui/QWidget>#include <QtCore>class Widget : public QWidget{    Q_OBJECT    public:    Widget(QWidget *parent = 0);    ~Widget();    void read_xml(QString filename);    void create_xml(QString filename);    void add_xmlnode(QString filename,QString rmt_name,QString ipa,QString ipb);    void do_xml(const QString opt,QString filename);private:};#endif // WIDGET_H

widget.cpp文件代码：

#include "widget.h"#include "qfile.h"#include "qdebug.h"#include <QDomDocument>#include "qtextcodec.h"Widget::Widget(QWidget *parent)    : QWidget(parent){    QTextCodec::setCodecForCStrings(QTextCodec::codecForName("GB2312"));    QFile *file;    QString  filename = "config.xml";    if(file->exists("config.xml"))    {        read_xml(filename);    }    else    {        create_xml(filename);    }    add_xmlnode(filename,"remote1","127.0.0.1","192.168.1.199");    do_xml("update",filename);}Widget::~Widget(){    }void Widget::do_xml(const QString opt,QString filename){    QFile file(filename);    if(!file.open(QIODevice::ReadOnly | QIODevice::Text))    {        qDebug() << "open for do erro";        file.close();    }    QDomDocument doc;    if(!doc.setContent(&file))     {        qDebug() << "setcontent for do error";        file.close();    }    file.close();    QDomNodeList lists = doc.elementsByTagName("remote");    QDomElement ele = lists.at(1).toElement();    if(ele.attribute(tr("id")) == "3")    {        if("delete" == opt || "update" == opt)        {            QDomElement root = doc.documentElement();            if("delete" == opt)            {                root.removeChild(lists.at(1));                qDebug() << "remove ok !";            }            else            {                QDomNodeList child=lists.at(1).childNodes();                child.at(0).toElement().firstChild().setNodeValue("namechanged");                child.at(1).toElement().firstChild().setNodeValue("ipachanged");                child.at(2).toElement().firstChild().setNodeValue("ipbchanged");                qDebug() << "modify ok !";            }            if(!file.open(QIODevice::WriteOnly | QIODevice::Text))            {                qDebug() << "open for remove error!";            }            QTextStream out(&file);            doc.save(out,4);            file.close();        }    }}void Widget::add_xmlnode(QString filename,QString rmt_name, QString ipa, QString ipb){    QFile file(filename);    if (!file.open(QIODevice::ReadOnly | QFile::Text)) {        qDebug()<<"open for add error..." ;    }    QDomDocument doc;    QString errorStr;    int errorLine;    int errorColumn;    if (!doc.setContent(&file, false, &errorStr, &errorLine, &errorColumn)) {        qDebug()<<"add setcontent error..." ;        file.close();    }    //QDomNode node = doc.firstChild();    file.close();    QDomElement root = doc.documentElement();    if(root.isNull())    {        root = doc.createElement("ipconfig");    }    QDomElement element_root = doc.createElement(tr("remote"));    QDomAttr attr_id = doc.createAttribute(tr("id"));    QDomElement element_rmt = doc.createElement(tr("rmt_name"));    QDomElement element_ipa = doc.createElement(tr("ipa"));    QDomElement element_ipb = doc.createElement(tr("ipb"));    QString str_id;    if(root.lastChild().isNull())    {        str_id = "1";        attr_id.setValue(str_id);    }    else    {        str_id = root.lastChild().toElement().attribute(tr("id"));        int count = str_id.toInt()+1;        attr_id.setValue(QString::number(count));    }    QDomText text;    text =doc.createTextNode(rmt_name);    element_rmt.appendChild(text);    text = doc.createTextNode(ipa);    element_ipa.appendChild(text);    text = doc.createTextNode(ipb);    element_ipb.appendChild(text);    text.clear();    element_root.appendChild(element_rmt);    element_root.appendChild(element_ipa);    element_root.appendChild(element_ipb);    element_root.setAttributeNode(attr_id);    root.appendChild(element_root);    if(!file.open(QIODevice::WriteOnly|QIODevice::Append))        qDebug() << "open for add error!";    QTextStream out(&file);    doc.save(out,4);    file.close();}void Widget::read_xml(QString filename){    QFile file(filename);    if (!file.open(QIODevice::ReadOnly | QFile::Text)) {        qDebug()<<"open for read error..." ;    }    QString errorStr;    int errorLine;    int errorColumn;    QDomDocument doc;    if (!doc.setContent(&file, false, &errorStr, &errorLine, &errorColumn)) {        qDebug()<<"setcontent error..." ;        file.close();    }    file.close();    QDomElement root = doc.documentElement();    if (root.tagName() != "ipconfig") {       qDebug()<<"root.tagname != ipconfig..." ;    }    QDomNode node = root.firstChild();    while(!node.isNull())    {        if(node.isElement())        {            QDomElement element = node.toElement();            qDebug() << qPrintable(element.tagName())<<qPrintable(element.attribute("id"));            QDomNodeList list = element.childNodes();            for(int i = 0;i < list.count();i++)            {                QDomNode nodechild = list.at(i);                if(nodechild.isElement())                {                    qDebug() << "    " << qPrintable(nodechild.toElement().tagName()) << qPrintable(nodechild.toElement().text());                }            }        }        node = node.nextSibling();    }}void Widget::create_xml(QString filename){    QFile file(filename);    file.open(QIODevice::ReadWrite);    QDomDocument doc;    QDomProcessingInstruction instruction;    instruction = doc.createProcessingInstruction("xml","version=\"1.0\" encoding=\"GB2312\"");    doc.appendChild(instruction);    QDomElement root = doc.createElement("ipconfig");    doc.appendChild(root);    QDomText text = doc.createTextNode("");    root.appendChild(text);    QTextStream out(&file);    doc.save(out,4);    file.close();}

main.cpp文件代码：

#include <QtGui/QApplication>#include "widget.h"int main(int argc, char *argv[]){    QApplication a(argc, argv);    Widget w;    w.show();        return a.exec();}

XML文件结构：

<?xml version='1.0' encoding='GB2312'?><ipconfig>    <remote id="1">        <rmt_name>remote1</rmt_name>        <ipa>127.0.0.1</ipa>        <ipb>192.168.1.199</ipb>    </remote>    <remote id="3">        <rmt_name>namechanged</rmt_name>        <ipa>ipachanged</ipa>        <ipb>ipbchanged</ipb>    </remote>    <remote id="4">        <rmt_name>remote1</rmt_name>        <ipa>127.0.0.1</ipa>        <ipb>192.168.1.199</ipb>    </remote>    <remote id="5">        <rmt_name>remote1</rmt_name>        <ipa>127.0.0.1</ipa>        <ipb>192.168.1.199</ipb>    </remote>    <remote id="6">        <rmt_name>remote1</rmt_name>        <ipa>127.0.0.1</ipa>        <ipb>192.168.1.199</ipb>    </remote>    <remote id="7">        <rmt_name>remote1</rmt_name>        <ipa>127.0.0.1</ipa>        <ipb>192.168.1.199</ipb>    </remote>    <remote id="8">        <rmt_name>remote1</rmt_name>        <ipa>127.0.0.1</ipa>        <ipb>192.168.1.199</ipb>    </remote></ipconfig>

应用程序输出：

remote 1

rmt_name remote1

ipa 127.0.0.1

ipb 192.168.1.199

remote 3

rmt_name remote1

ipa 127.0.0.1

ipb 192.168.1.199

remote 4

rmt_name remote1

ipa 127.0.0.1

ipb 192.168.1.199

remote 5

rmt_name remote1

ipa 127.0.0.1

ipb 192.168.1.199

remote 6

rmt_name remote1

ipa 127.0.0.1

ipb 192.168.1.199

remote 7

rmt_name remote1

ipa 127.0.0.1

ipb 192.168.1.199

modify ok !