先说几句重点:
1,tinyxml 生成或解析XML非常好用
2,tinyxml 利用DOM(文档对象模型) *** 作XML,根节点与各个子节点相当于形成一棵树
3,只要了解tinyxml的用法,可以只new对象而不用delete。
4,tinyxml包含6个文件 tinystr.cpp , tinystr.h , tinyxml.cpp , tinyxmlerror.cpp , tinyxml.h , tinyxmlparser.cpp
5,来个官网说明的class inheritance,官网地址:http://www.grinninglizard.com/tinyxmldocs/index.html
This inheritance list is sorted roughly, but not completely, alphabetically:
- TiXmlBase
- TiXmlAttribute
- TiXmlNode
- TiXmlComment
- TiXmlDeclaration
- TiXmlDocument
- TiXmlElement
- TiXmlText
- TiXmlUnknown
- TiXmlHandle
- TiXmlVisitor
- TiXmlPrinter
直接上程序,只要看完代码,就会处理最简单的XML文档了
#include <stdio.h>
#include "tinyxml.h" int CreateXml()
{
//创建一个XML结构
TiXmlDocument* pDoc = new TiXmlDocument();
//创建一个根节点并连接到XML
TiXmlElement* pRoot = new TiXmlElement("item");
pDoc->LinkEndChild(pRoot);
//创建一个name子节点并连接根节点下
TiXmlElement* nameElement = new TiXmlElement("name");
pRoot->LinkEndChild(nameElement);
nameElement->SetAttribute("ID","");
TiXmlText* nameContent = new TiXmlText("opop");
nameElement->LinkEndChild(nameContent); TiXmlElement* addrElement = new TiXmlElement("addr");
pRoot->LinkEndChild(addrElement);
TiXmlText* addrContent = new TiXmlText("guangzhou");
addrElement->LinkEndChild(addrContent); TiXmlElement* telElement = new TiXmlElement("tel");
pRoot->LinkEndChild(telElement);
TiXmlText* telContent = new TiXmlText("");
telElement->LinkEndChild(telContent); TiXmlElement* emailElement = new TiXmlElement("email");
pRoot->LinkEndChild(emailElement);
TiXmlText* emailContent = new TiXmlText("[email protected]");
emailElement->LinkEndChild(emailContent);
//保存到文件
pDoc->SaveFile("test.xml");
delete pDoc; //应该是必要的
return ; } int ReadXml()
{
//创建一个XML结构并载入文件内容
TiXmlDocument* pDoc = new TiXmlDocument();
pDoc->LoadFile("test.xml");
pDoc->Print();
//获取根节点
TiXmlElement* pRoot = pDoc->RootElement();
printf("%s\n",pRoot->Value());
//获取根节点下的子节点并打印其内容
TiXmlElement* pChild = pRoot->FirstChildElement("name");
printf("%s\n",pChild->FirstChild()->ToText()->Value()); pChild = pRoot->FirstChildElement("addr");
printf("%s\n",pChild->FirstChild()->ToText()->Value()); pChild = pRoot->FirstChildElement("tel");
printf("%s\n",pChild->FirstChild()->ToText()->Value()); pChild = pRoot->FirstChildElement("email");
printf("%s\n",pChild->FirstChild()->ToText()->Value()); delete pDoc;//应该是必要的
} int main() { CreateXml(); ReadXml(); return ; }
结果如下:
最后再说一个重点:关于delete的问题
先看下面一段官方代码:只有new,没有delete
void write_simple_doc2( )
{
// same as write_simple_doc1 but add each node
// as early as possible into the tree. TiXmlDocument doc;
TiXmlDeclaration * decl = new TiXmlDeclaration( "1.0", "", "" );
doc.LinkEndChild( decl ); TiXmlElement * element = new TiXmlElement( "Hello" );
doc.LinkEndChild( element ); TiXmlText * text = new TiXmlText( "World" );
element->LinkEndChild( text ); doc.SaveFile( "madeByHand2.xml" );
}
Both of these produce the XML:
<?xml version="1.0" ?>
<Hello>World</Hello>
对比完就发现了,只要代码中TiXmlDocument 对象不要在堆中new,直接在栈中生成,那么,就不需要任何delete *** 作,而且必须不能delete,否则就出问题了。
原因很简单,只要TiXmlDocument 对象这个基本结构被销毁了,所有的节点会被自动销毁,源代码实现了该功能
所以,使用时只要保证TiXmlDocument 类型的对象正确被释放就可以了
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