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This article mainly introduces "how C++ uses TinyXML to parse XML". In daily operation, I believe many people have doubts about how C++ uses TinyXML to parse XML. The editor consulted all kinds of materials and sorted out simple and easy-to-use methods of operation. I hope it will be helpful to answer the doubts about "how C++ uses TinyXML to analyze XML". Next, please follow the editor to study!

1. Introduction

The official website of Tinyxml: http://www.grinninglizard.com

Official introduction document: http://www.grinninglizard.com/tinyxmldocs/tutorial0.html

In TinyXML, some classes are defined based on the various elements of XML:

TiXmlBase: the base class of the entire TinyXML model.

TiXmlAttribute: attributes that correspond to elements in XML.

TiXmlNode: corresponds to a node in the DOM structure.

TiXmlComment: corresponds to comments in XML

TiXmlDeclaration: corresponds to the declaration section of the XML, that is.

TiXmlDocument: the entire document corresponding to XML.

TiXmlElement: the element corresponding to XML.

TiXmlText: the text portion corresponding to XML

TiXmlUnknown: corresponds to the unknown part of the XML.

TiXmlHandler: defines some operations for XML.

Use the following figure to illustrate the text format for commonly used classes:

/ / TiXmlDeclaration, declare / / TiXmlElement, element / / TiXmlComment, comment / / TiXmlElement, element Welcome to MyApp// is element TiXmlElement, "Welcome to MyApp" is TiXmlText, text Thank you for using MyApp// is the same as above / / TiXmlElement, element / / Window is element TiXmlElement, name, x, y, h are TiXmlAttribute

TinyXML is a parsing library, which is mainly composed of DOM model classes (TiXmlBase, TiXmlNode, TiXmlAttribute, TiXmlComment, TiXmlDeclaration, TiXmlElement, TiXmlText, TiXmlUnknown) and TiXmlHandler classes. It consists of two header files (.h file) and four CPP files (.cpp file). When you use it, you can use it as long as you import (tinyxml.h, tinystr.h, tinystr.cpp, tinyxml.cpp, tinyxmlerror.cpp, tinyxmlparser.cpp) into the project. If necessary, you can make it your own DLL to call.

Note that TiXmlBase is the base class for TiXmlNode, and TiXmlNode is the base class for TiXmlElement, TiXmlComment, TiXmlText, TiXmlDeclaration, TiXmlUnknown, and TiXmlDocument.

2.TinyXML configuration

Add the header file reference # include "tinyxml/tinyxml.h" to the stdafxh header file

Add lib reference library to the project settings

Add a dynamic library reference to stdafx.h

# ifdef _ DEBUG#pragma comment (lib, "TinyXMLD.lib") # else#pragma comment (lib, "TinyXML.lib") # endif3.TinyXML read and save file 3.1 read xml file TiXmlDocument lconfigXML;if (! lconfigXML.LoadFile (strXmlFile.c_str ())) {break;} 3.2 read xml parameter TiXmlDocument lActionXML;lActionXML.Parse (strRmcpParam.c_str ()); if (lActionXML.Error ()) {strErr = "input parameter is not in standard xml format" Return false;} 3.3Save xml parameters to the text TiXmlDocument tyDoc;. TyDoc.SaveFile (m_strFilePath); 3.4 saves the xml parameter to the temporary variable TiXmlDocument tyDoc;. TiXmlPrinter printer;tyDoc.Accept (& printer); std::string devParam = std::string (printer.CStr ()); 4.TinyXML addition, deletion, modification and search 4.1 increase

Create a xml file code such as in 1

Void write_app_settings_doc () {TiXmlDocument doc; TiXmlElement* msg; TiXmlDeclaration* decl = new TiXmlDeclaration; doc.LinkEndChild (decl); TiXmlElement* root = new TiXmlElement ("MyApp"); doc.LinkEndChild (root); TiXmlComment * comment = new TiXmlComment (); comment- > SetValue ("Settings for MyApp"); root- > LinkEndChild (comment) TiXmlElement * msgs = new TiXmlElement ("Messages"); root- > LinkEndChild (msgs); msg = new TiXmlElement ("Welcome"); msg- > LinkEndChild ("Welcome to MyApp"); msgs- > LinkEndChild (msg); msg = new TiXmlElement ("Farewell"); msg- > LinkEndChild (new TiXmlText ("Thank you for using MyApp")); msgs- > LinkEndChild (msg) TiXmlElement * windows = new TiXmlElement ("Windows"); root- > LinkEndChild (windows); TiXmlElement * window; window = new TiXmlElement ("Window"); windows- > LinkEndChild (window); window- > SetAttribute ("name", "MainFrame"); window- > SetAttribute ("x", 5); window- > SetAttribute ("y", 15); window- > SetAttribute ("w", 400); window- > SetAttribute ("h", 250) TiXmlElement * cxn = new TiXmlElement ("Connection"); root- > LinkEndChild (cxn); cxn- > SetAttribute ("ip", "192.168.0.1"); cxn- > SetDoubleAttribute ("timeout", 123.456); / / floating point attrib dump_to_stdout (& doc); doc.SaveFile ("appsettings.xml");}

Insert a new node at the end of the node

TiXmlNode* LinkEndChild (TiXmlNode* addThis)

Insert a new node before / after the node

TiXmlNode* InsertBeforeChild (TiXmlNode* beforeThis, const TiXmlNode& addThis); TiXmlNode* InsertAfterChild (TiXmlNode* afterThis, const TiXmlNode& addThis); 4.2 Delete

Delete a node. TiXmlNode is the base class of TiXmlElement, TiXmlComment, TiXmlText, TiXmlDeclaration, TiXmlUnknown, TiXmlDocument

TiXmlNode node;node.Clear ()

Remove child node B from node A

TiXmlNode nodeA;nodeA. RemoveChild (TiXmlNode* removeThis)

Remove an attribute named B from element A

TiXmlAttribute attrA;attrA. RemoveAttribute (const char * name)

The search is, now you need to change 1234 to a different value.

TiXmlNode* lpnode = NULL;lpnode = tixml.RootElement ()-> IterateChildren ("mfid", lpnode); TiXmlAttribute* tiattr = lpnode- > ToElement ()-> FirstAttribute (); / / find the mfid node and get the first attribute value. Note that if there are multiple attribute values, you need to determine which attribute value is the required tiattr- > SetValue (mfid.c_str ())

Replace a node

TiXmlNode* ReplaceChild (TiXmlNode* replaceThis, const TiXmlNode& withThis); 4.4 check

Get the link node

Const TiXmlNode* lpItemNode = NULL;// initialization lpItemNode = lconfigXML.RootElement ()-> IterateChildren ("link", lpItemNode); if (lpItemNode = = NULL) {/ / Can not find break;}

Get the value of the type attribute in the link node

Std::string strType = lpItemNode- > ToElement ()-> Attribute ("type")

Ergodic node

Const TiXmlNode* lpMapNode = NULL; / / initialize lpMapNode = lconfigXML.RootElement ()-> IterateChildren ("node", lpMapNode); if (lpMapNode) {rms::CStationMapping litem; const TiXmlNode* lpItemNode = NULL; while (lpItemNode = lpMapNode- > IterateChildren ("item", lpItemNode)) {string str = lpItemNode- > ToElement ()-> Attribute ("ABC");}}

Traversing element attributes

TiXmlAttribute* pAttr = NULL; for (pAttr = pNode- > FirstAttribute (); pAttr; pAttr = pAttr- > Next ()) {... }

The next sibling node of the node

Const TiXmlNode* NextSibling () const

Next element of the element

Const TiXmlElement* NextSiblingElement () const

The next property of the property

Const TiXmlAttribute* Next () const

The return value of NULL indicates that it does not exist.

5. A complete example

Void AppSettings::load (const char* pFilename) {TiXmlDocument doc (pFilename); if (! doc.LoadFile ()) return; TiXmlHandle hDoc (& doc); TiXmlElement* pElem; TiXmlHandle hRoot (0); / / block: name {pElem=hDoc.FirstChildElement (). Element (); / / should always have a valid root but handle gracefully if it does if (! pElem) return; / / save this for later hRoot=TiXmlHandle (pElem);} / / block: string table {m_messages.clear (); / / trash existing table pElem=hRoot.FirstChild ("Messages"). FirstChild (). Element (); for (pElem; pElem; pElem=pElem- > NextSiblingElement ()) {const char * pKey=pElem- > Value (); const char * pText=pElem- > GetText () If (pKey & & pText) {m _ messages [PKey] = pText;}} / / block: windows {m_windows.clear (); / / trash existing list TiXmlElement* pWindowNode=hRoot.FirstChild ("Windows"). FirstChild (). Element (); for (pWindowNode; pWindowNode) PWindowNode=pWindowNode- > NextSiblingElement () {WindowSettings w; const char * pName=pWindowNode- > Attribute ("name"); if (pName) W. namename; pWindowNode- > QueryIntAttribute ("x", & W.X); / / If this fails, original value is left as-is pWindowNode- > QueryIntAttribute ("y", & W.Y) PWindowNode- > QueryIntAttribute ("w", & W.W); pWindowNode- > QueryIntAttribute ("hh", & W.H); m_windows.push_back (w);} / / block: connection {pElem=hRoot.FirstChild ("Connection"). Element (); if (pElem) {missuconnection.iproompElm-> Attribute ("ip") PElem- > QueryDoubleAttribute ("timeout", & m_connection.timeout);} this ends the study of "how C++ uses TinyXML to parse XML". I hope I can solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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