服务器开发24：tinyxml使用(服务器起服读取配置信息接口)

一、tinyxml代码介绍

二、代码使用说明

1）包裹头文件和动态库引用

• 1）在stdafx.h头文件中增加头文件引用#include “tinyxml/tinyxml.h”

• 2）在stdafx.h中加入动态库引用

#ifdef _DEBUG
#pragma comment(lib,"TinyXMLD.lib")
#else
#pragma comment(lib,"TinyXML.lib")
#endif
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2）基础操作：读取xml文件

TiXmlDocument lconfigXML;
if( !lconfigXML.LoadFile( strXmlFile.c_str() ) )
{
    break;
}
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3）基础操作：保存xml参数到文本

TiXmlDocument tyDoc;
…
tyDoc.SaveFile(m_strFilePath);
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4）增：举例生成xml文件

• 举例要生成的xml

<?xml version="1.0" ?> //TiXmlDeclaration,声明
<MyApp>    //TiXmlElement,元素
    <!-- Settings for MyApp -->//TiXmlComment，注释
    <Messages>//TiXmlElement,元素
        <Welcome>Welcome to MyApp</Welcome>
//<Welcome>是元素TiXmlElement ，“Welcome to MyApp”是TiXmlText,文本
        <Farewell>Thank you for using MyApp</Farewell>//同上
    </Messages>
    <Windows>//TiXmlElement,元素
        <Window name="MainFrame" x="5" y="15" w="400" h="250" />
// Window是元素TiXmlElement ，name、x、y、h是TiXmlAttribute
    </Windows>
    <Connection ip="192.168.0.1" timeout="123.456000" />
</MyApp>
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• 创建上面xml的代码

void write_app_settings_doc( )  
{  
    TiXmlDocument doc;  
    TiXmlElement* msg;
    //1、写声明
    TiXmlDeclaration* decl = new TiXmlDeclaration( "1.0", "", "" );  
    doc.LinkEndChild( decl );   
    
    //2、创建根元素MyApp
    TiXmlElement * root = new TiXmlElement( "MyApp" );  
    doc.LinkEndChild( root );  
	
	//3、创建注释-Settings for MyApp
    TiXmlComment * comment = new TiXmlComment();
    comment->SetValue(" Settings for MyApp " );  
    root->LinkEndChild( comment );   
	
	//4、在MyApp下面创建Message这个元素
    TiXmlElement * msgs = new TiXmlElement( "Messages" );  
    root->LinkEndChild( msgs );   //注意这是用root调用

	//5、在Message下面创建新元素Welconme
    msg = new TiXmlElement( "Welcome" );  
    msg->LinkEndChild( new TiXmlText( "Welcome to MyApp" ));  
    msgs->LinkEndChild( msg );   
	
	//6、在Message下面创建新元素Farewell
    msg = new TiXmlElement( "Farewell" );  
    msg->LinkEndChild( new TiXmlText( "Thank you for using MyApp" ));  
    msgs->LinkEndChild( msg );   

	//7、在root下创建新元素windwos
    TiXmlElement * windows = new TiXmlElement( "Windows" );  
    root->LinkEndChild( windows );  

	//8、填充window
    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);

	//9、在root下创建connection这个元素
    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" );  
} 
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5）改：修改节点值

• 查找内容为，现需要将1234改成其他值

TiXmlNode* lpnode = NULL;
lpnode = tixml.RootElement()->IterateChildren("mfid",lpnode);
TiXmlAttribute* tiattr = lpnode->ToElement()->FirstAttribute();
//找到mfid节点，获取第一个属性值。注意，如果有多个属性值，需要判断哪个属性值是需要的
tiattr->SetValue(mfid.c_str());
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• 替换一个节点

TiXmlNode* ReplaceChild( TiXmlNode* replaceThis, const TiXmlNode& withThis ); 
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6）查：寻找某个节点（返回字符串）\遍历节点或节点的属性

• 获取link节点

const TiXmlNode* lpItemNode = NULL;//初始化
lpItemNode = lconfigXML.RootElement()->IterateChildren("link", lpItemNode);
if (lpItemNode == NULL)
{
    //Can not find break;
}
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• 获取link节点中的type属性值(返回字符串)

std::string strType = lpItemNode->ToElement()->Attribute("type");
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• 遍历节点

const TiXmlNode* lpMapNode = NULL; //初始化
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"); 
    }
}
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• 遍历元素属性

TiXmlAttribute* pAttr = NULL; 
for (pAttr = pNode->FirstAttribute(); pAttr; pAttr = pAttr->Next())  
{    
　　…
}
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• 节点的下一个兄弟节点

const TiXmlNode* NextSibling() const;
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• 元素的下一个元素

const TiXmlElement* NextSiblingElement() const;
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• 属性的下一个属性

const TiXmlAttribute* Next() const;
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返回值为NULL表示不存在

7）删：删除节点信息

• 备注

TiXmlNode是TiXmlElement、TiXmlComment、TiXmlText、TiXmlDeclaration、TiXmlUnknown、TiXmlDocument的基类

TiXmlNode node;
node.Clear();
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• 从A节点上移除子节点B

TiXmlNode nodeA;
nodeA. RemoveChild( TiXmlNode* removeThis );
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• 从元素A上移除名字为B的属性

TiXmlAttribute attrA;
attrA. RemoveAttribute( const char * name );
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三、整体代码举例

1）基础类举例

#include 
#include 
using namespace std;

typedef std::map<std::string,std::string> MessageMap;

// a basic window abstraction - demo purposes only
class WindowSettings
{
public:
	int x,y,w,h;
	string name;

	WindowSettings()
		: x(0), y(0), w(100), h(100), name("Untitled")
	{
	}

	WindowSettings(int x, int y, int w, int h, const string& name)
	{
		this->x=x;
		this->y=y;
		this->w=w;
		this->h=h;
		this->name=name;
	}
};

class ConnectionSettings
{
public:
	string ip;
	double timeout;
};

class AppSettings
{
public:
	string m_name;
	MessageMap m_messages;
	list<WindowSettings> m_windows;
	ConnectionSettings m_connection;

	AppSettings() {}

	void save(const char* pFilename);
	void load(const char* pFilename);
	
	// just to show how to do it
	void setDemoValues()
	{
		m_name="MyApp";
		m_messages.clear();
		m_messages["Welcome"]="Welcome to "+m_name;
		m_messages["Farewell"]="Thank you for using "+m_name;
		m_windows.clear();
		m_windows.push_back(WindowSettings(15,15,400,250,"Main"));
		m_connection.ip="Unknown";
		m_connection.timeout=123.456;
	}
};
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2）实际操作xml函数(加载)

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;
        m_name=pElem->Value();

        // 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.name=pName;
            
            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)
        {
            m_connection.ip=pElem->Attribute("ip");
            pElem->QueryDoubleAttribute("timeout",&m_connection.timeout);
        }
    }
}
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3）保存某个xml（save）

void AppSettings::save(const char* pFilename)
{
	TiXmlDocument doc;  
	TiXmlElement* msg;
	TiXmlComment * comment;
	string s;
 	TiXmlDeclaration* decl = new TiXmlDeclaration( "1.0", "", "" );  
	doc.LinkEndChild( decl ); 
 
	TiXmlElement * root = new TiXmlElement(m_name.c_str());  
	doc.LinkEndChild( root );  

	comment = new TiXmlComment();
	s=" Settings for "+m_name+" ";
	comment->SetValue(s.c_str());  
	root->LinkEndChild( comment );  

	// block: messages
	{
		MessageMap::iterator iter;

		TiXmlElement * msgs = new TiXmlElement( "Messages" );  
		root->LinkEndChild( msgs );  
 
		for (iter=m_messages.begin(); iter != m_messages.end(); iter++)
		{
			const string & key=(*iter).first;
			const string & value=(*iter).second;
			msg = new TiXmlElement(key.c_str());  
			msg->LinkEndChild( new TiXmlText(value.c_str()));  
			msgs->LinkEndChild( msg );  
		}
	}

	// block: windows
	{
		TiXmlElement * windowsNode = new TiXmlElement( "Windows" );  
		root->LinkEndChild( windowsNode );  

		list<WindowSettings>::iterator iter;

		for (iter=m_windows.begin(); iter != m_windows.end(); iter++)
		{
			const WindowSettings& w=*iter;

			TiXmlElement * window;
			window = new TiXmlElement( "Window" );  
			windowsNode->LinkEndChild( window );  
			window->SetAttribute("name", w.name.c_str());
			window->SetAttribute("x", w.x);
			window->SetAttribute("y", w.y);
			window->SetAttribute("w", w.w);
			window->SetAttribute("h", w.h);
		}
	}

	// block: connection
	{
		TiXmlElement * cxn = new TiXmlElement( "Connection" );  
		root->LinkEndChild( cxn );  
		cxn->SetAttribute("ip", m_connection.ip.c_str());
		cxn->SetDoubleAttribute("timeout", m_connection.timeout); 
	}

	doc.SaveFile(pFilename);  
}
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