QT之XML的解析与生成

    QFile file(ui->comboBox->currentText());
    //打开文件
    bool isOK = file.open(QIODevice::ReadOnly | QIODevice::Text);
    if(isOK){
        QXmlStreamReader reader(&file);
        while(!reader.atEnd())
        {
            //判断是否是节点的开始
            if(reader.isStartElement())
            {
                QXmlStreamAttributes attributes = reader.attributes();
                // headList代表要解析的值的对象
                for(int i = 0; i < headList.size(); i++){
                    QString str = valueList.at(i);
                    QStringList strList = str.split(",");
                    if(reader.name() == headList.at(i)){
                        for(int j = 0; j < strList.size(); j++){
                            ui->textEdit_2->append(strList.at(j)+": " + attributes.value(strList.at(j)).toString());
                        }
                    }
                }
            }
            reader.readNext();
        }
    }
    else
    {
        qDebug()<<"Open file hello.xml failure";
    }
    file.close();                    

    //这里是以树的结构来生成XML的，最多3层
    QDomElement element, root, cElement,sElement;
    QDomProcessingInstruction instruction;//写入xml的头部，添加处理命令
    instruction = doc.createProcessingInstruction( "xml", "version = \‘1.0\‘ encoding=\‘UTF-8\‘" );//设置xml的版本号和字节的格式
    doc.appendChild(instruction);//添加介绍

    root = doc.createElement("XML");//设置根节点为COMMAND
    doc.appendChild(root);

    for(int i = 0; i < ui->treeWidget->topLevelItemCount(); i++){   // 获取父节点个数
        element = doc.createElement( "OBJECT" );//添加根节点下面的元素OBJECT
        for(int count = 0; count < ui->treeWidget->columnCount(); count++){     // 获取所在列的数据
            element.setAttribute("name", ui->treeWidget->topLevelItem(i)->text(count));
            root.appendChild(element);
        }
        for(int j=0; j < ui->treeWidget->topLevelItem(i)->childCount(); j++){
            cElement = doc.createElement("paramer");
            for(int count = 0; count < ui->treeWidget->columnCount(); count++){
                cElement.setAttribute("name", ui->treeWidget->topLevelItem(i)->child(j)->text(count));
                element.appendChild(cElement);
            }
            for(int k=0; k < ui->treeWidget->topLevelItem(i)->child(j)->childCount(); j++){
                sElement = doc.createElement("packet");
                for(int count = 0; count < ui->treeWidget->columnCount(); count++){
                    sElement.setAttribute("name", ui->treeWidget->topLevelItem(i)->child(j)->child(k)->text(count));
                    cElement.appendChild(sElement);
                }
            }
        }
    }
　　QFile file(fileName);
    if(!file.open(QIODevice::WriteOnly | QIODevice::Truncate)){
        qDebug() << file.errorString();
        return;
    }
    QTextStream out(&file);
    doc.save(out, 4);