QT中XML增删改查，不会有重复beta

最近在做QT项目，要把一些配置内容写入xml中，网上没有一个可以概括xml增删改查的内容，现在写一篇，包含完整的增删改查，测试通过，具体代码如下：

其中的测试代码见mainwindows.cpp里面，里面有创建xml文件，增加数据，删除数据，修改数据，查询数据，其中没有重复内容。删除的时候也把相同的标签全部删掉了。

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);

XMLParser *xmlparser = new XMLParser("D:/","test.xml");

QFile *file;
//QString  filename = "D:/test.xml";
if(!file->exists("D:/test.xml"))  {
xmlparser->create_xml("D:/","test.xml");

}
bool ret = xmlparser->add_element("D:/","test.xml","password","12345");

QString password = xmlparser->get_element("D:/","test.xml","password");

qDebug()<<"password is "<<password;

bool ret01 = xmlparser->update_element("D:/","test.xml","password","342345");

bool ret02 = xmlparser->delete_element("D:/","test.xml","password","1212342345");
qDebug()<<"ret02 is "<<ret02;

bool ret03 = xmlparser->delete_element("D:/","test.xml","password","342345");
qDebug()<<"ret03 is "<<ret03;

//    QString path = xmlparser->get_savepath();

//    if(NULL==path||path==""){
//        QString fileName = QFileDialog::getExistingDirectory(this, tr("请选择保存目录"),
//                                                          "",
//                                                       QFileDialog::ShowDirsOnly
//                                                          | QFileDialog::DontResolveSymlinks);
//        qDebug()<<"fileName is "<<fileName;
//        bool ret = xmlparser->set_savepath(fileName);
//        qDebug()<<"ret is "<<ret;
//    }else{
//        qDebug()<<"path is "<<path;
//    }

}

MainWindow::~MainWindow()
{

delete ui;
}

xmlparser.cpp

#include "xmlparser.h"

#define __XMLPARSER_DEBUG__

XMLParser::XMLParser(QObject *parent) : QObject(parent)
{

configPath = dir.currentPath()+"/setting.xml";
file=new QFile(configPath);

}

XMLParser::XMLParser(QString filepath ,QString filename,QObject *parent) : QObject(parent)
{
this->filepath = filepath;
this->filename=filename;

}

QString XMLParser::get_savepath(){

QDomDocument dom;

if(file->open(QIODevice::ReadOnly))
{
dom.setContent(file);
}else{
return NULL;
}
QDomNodeList save_path=dom.elementsByTagName("save_path");

int elementnum = save_path.count();
QString savepath = save_path.item(0).toElement().text();

file->close();
if(NULL!=savepath&&savepath!=""){
return savepath;
}else{
return NULL;
}

}

bool XMLParser::set_savepath(QString path){

if(NULL==path||path==""){
return false;
}
if(!file->open(QIODevice::WriteOnly|QIODevice::ReadOnly))
{
return false;
}

QDomDocument doc;
QDomText text;
QDomElement element;
QDomProcessingInstruction instruction;
instruction=doc.createProcessingInstruction("xml","version=\'1.0\'");
doc.appendChild(instruction);
QDomElement root=doc.createElement("root");
doc.appendChild(root);
QDomElement general=doc.createElement("general");
root.appendChild(general);

element=doc.createElement("save_path");
text=doc.createTextNode(path);
element.appendChild(text);
general.appendChild(element);

QTextStream out(file);
doc.save(out,4);
file->close();

return true;
}

QString XMLParser::get_element(QString filepath ,QString filename,QString elementstr){
if(NULL==filepath||NULL==filename||NULL==elementstr){
return NULL;
}
QString Path = filepath+filename;
//QString Path = filepath.endsWith("/")?filepath+filename:filepath.mid(0,filepath.length()-1);+filename;
QFile myfile(Path);
QDomDocument dom;

if(myfile.open(QIODevice::ReadOnly))
{
QString errorStr;
int errorLine;
int errorColumn;

//QDomDocument doc;
if (!dom.setContent(&myfile, false, &errorStr, &errorLine, &errorColumn)) {
#ifdef __XMLPARSER_DEBUG__
qDebug()<<"setcontent error..."<<" errorStr is "<<errorStr<<" errorLine is "<<errorLine<<" errorColumn is "<<errorColumn ;
#endif
myfile.close();
}
myfile.close();

//dom.setContent(myfile);
}else{
#ifdef __XMLPARSER_DEBUG__
qDebug()<<"open xml read error..." ;
#endif
return NULL;
}

QDomElement root = dom.documentElement();
if (root.tagName() != "root") {
#ifdef __XMLPARSER_DEBUG__
qDebug()<<"root.tagname != root..." ;
#endif
}

QDomNode node = root.firstChild();
while(!node.isNull())
{
if(node.isElement()){
QDomElement element = node.toElement();
#ifdef __XMLPARSER_DEBUG__
qDebug()<<"tagName is "<<element.tagName()<<" element.text is "<<element.text();
#endif

if(element.tagName()==elementstr){
return (element.text().length()>0&&NULL!=element.text())?element.text():NULL;
}

}
node = node.nextSibling();
}
return NULL;

//    QDomNodeList save_path=dom.elementsByTagName(element);

//    int elementnum = save_path.count();
//    QString savepath = save_path.item(0).toElement().text();

//    myfile->close();
//    if(NULL!=savepath&&savepath!=""){
//        return savepath;
//    }else{
//        return NULL;
//    }

}

bool XMLParser::add_element(QString filepath ,QString filename,QString element,QString value){

#ifdef __XMLPARSER_DEBUG__
qDebug()<<"in add_element";
#endif
if(NULL==filepath||NULL==filename||NULL==element||NULL==value){
return NULL;
}
//QString Path = filepath.endsWith("/")?filepath+filename:filepath.mid(0,filepath.length()-1);+filename;

QString Path = filepath+filename;

QFile myfile(Path);
if(!myfile.open(QIODevice::WriteOnly|QIODevice::ReadOnly))
{
return false;
}

QDomDocument doc;
QString errorStr;
int errorLine;
int errorColumn;

if (!doc.setContent(&myfile, false, &errorStr, &errorLine, &errorColumn)) {
#ifdef __XMLPARSER_DEBUG__
qDebug()<<"setcontent error..."<<" errorStr is "<<errorStr<<" errorLine is "<<errorLine<<" errorColumn is "<<errorColumn ;
#endif
myfile.close();
}
myfile.close();
QDomElement root = doc.documentElement();
if(root.isNull())
{
root = doc.createElement("root");
}

bool if_exist = false;
QDomNode node = root.firstChild();
while(!node.isNull())
{
if(node.isElement()){
QDomElement local_element = node.toElement();
#ifdef __XMLPARSER_DEBUG__
qDebug()<<"tagName is "<<local_element.tagName()<<" element.text is "<<local_element.text();

#endif
if(local_element.tagName()==element){
if_exist = true;
break;
}

}
node = node.nextSibling();
}

if(!if_exist){
QDomElement element_my = doc.createElement(element);
QDomText text;
text =doc.createTextNode(value);
element_my.appendChild(text);
root.appendChild(element_my);
}
#ifdef __XMLPARSER_DEBUG__
qDebug()<<"element is "<<element;
qDebug()<<"value is "<<value;
#endif
if(!myfile.open(QIODevice::WriteOnly)){
#ifdef __XMLPARSER_DEBUG__
qDebug() << "open for add error!";
#endif
}
QTextStream out(&myfile);
doc.save(out,4);
myfile.close();

return true;

}

void XMLParser::create_xml(QString filepath ,QString filename){
#ifdef __XMLPARSER_DEBUG__
qDebug()<<"in create_xml";
#endif
if(NULL==filepath||NULL==filename){
return;
}
QString Path = filepath+filename;
//QString Path = filepath.endsWith("/")?filepath+filename:filepath.mid(0,filepath.length()-1);+filename;
QFile myfile(Path);
myfile.open(QIODevice::ReadWrite);

QDomDocument doc;
QDomProcessingInstruction instruction;
instruction = doc.createProcessingInstruction("xml","version=\'1.0\'");
doc.appendChild(instruction);
QDomElement root = doc.createElement("root");

doc.appendChild(root);
QDomText text = doc.createTextNode("");
root.appendChild(text);
QTextStream out(&myfile);
doc.save(out,4);
myfile.close();
return;
}

bool XMLParser::update_element(QString filepath ,QString filename,QString element,QString value){
bool if_sucess = false;
if(NULL==filepath||NULL==filename||NULL==element||NULL==value){
return false;
}

QString Path = filepath+filename;

QFile myfile(Path);
QDomDocument doc;
QString errorStr;
int errorLine;
int errorColumn;

if (!doc.setContent(&myfile, false, &errorStr, &errorLine, &errorColumn)) {
#ifdef __XMLPARSER_DEBUG__
qDebug()<<"setcontent error..."<<" errorStr is "<<errorStr<<" errorLine is "<<errorLine<<" errorColumn is "<<errorColumn ;
#endif
myfile.close();
}

myfile.close();

QDomElement root = doc.documentElement();

QDomNodeList lists = doc.elementsByTagName(element);

//新建节点
QDomElement newNodeTag = doc.createElement(element);
QDomText newNodeText = doc.createTextNode(value);
newNodeTag.appendChild(newNodeText);

int num = 0;
for(num = 0;num<lists.size();num++){
QDomElement ele = lists.at(num).toElement();
#ifdef __XMLPARSER_DEBUG__
qDebug() << "element text is "<<ele.text();

#endif
//把老的节点替换成新建节点
root.replaceChild(newNodeTag,ele);
if_sucess = true;
#ifdef __XMLPARSER_DEBUG__
qDebug() << "modify ok ! value is "<<value;
#endif
}

if(!myfile.open(QIODevice::WriteOnly | QIODevice::Text))
{
#ifdef __XMLPARSER_DEBUG__
qDebug() << "open for remove error!";
#endif
}
QTextStream out(&myfile);
doc.save(out,4);
myfile.close();
if(if_sucess){
return if_sucess;
}else{
return if_sucess;
}
//    return true;

}

bool XMLParser::delete_element(QString filepath ,QString filename,QString element,QString value){
if(NULL==filepath||NULL==filename||NULL==element||NULL==value){
return false;
}

QString Path = filepath+filename;
bool if_sucess = false;
QFile myfile(Path);
QDomDocument doc;
QString errorStr;
int errorLine;
int errorColumn;

if (!doc.setContent(&myfile, false, &errorStr, &errorLine, &errorColumn)) {
#ifdef __XMLPARSER_DEBUG__
qDebug()<<"setcontent error..."<<" errorStr is "<<errorStr<<" errorLine is "<<errorLine<<" errorColumn is "<<errorColumn ;
#endif
myfile.close();
}

myfile.close();

QDomElement root = doc.documentElement();

QDomNodeList lists = doc.elementsByTagName(element);

//新建节点
QDomElement newNodeTag = doc.createElement(element);
QDomText newNodeText = doc.createTextNode(value);
newNodeTag.appendChild(newNodeText);

int num = 0;
for(num = 0;num<lists.size();num++){
QDomElement ele = lists.at(num).toElement();
#ifdef __XMLPARSER_DEBUG__
qDebug() << "element text is "<<ele.text();
#endif

//删除节点
if(ele.text()==value){
root.removeChild(ele);
if_sucess = true;
}
#ifdef __XMLPARSER_DEBUG__
qDebug() << "modify ok ! value is "<<value;
#endif
}

if(!myfile.open(QIODevice::WriteOnly | QIODevice::Text))
{
#ifdef __XMLPARSER_DEBUG__
qDebug() << "open for remove error!";
#endif
}
QTextStream out(&myfile);
doc.save(out,4);
myfile.close();
if(if_sucess){
return if_sucess;
}else{
return if_sucess;
}

}

XMLParser::~XMLParser(){
if(NULL!=file){
file->close();
file=NULL;
}
}

打印的结果是

in add_element
element is  "password"
value is  "12345"
tagName is  "password"  element.text is  "12345"
password is  "12345"
element text is  "12345"
modify ok ! value is  "342345"
element text is  "342345"
modify ok ! value is  "1212342345"
ret02 is  false
element text is  "342345"
modify ok ! value is  "342345"
ret03 is  true

代码已经放到github上，另外，也放到了csdn资源上 https://github.com/buptis073114/XMLParseExample