使用rapidxml操作xml~读写文件操作(转)

rapidxml~网上很容易下，下面介绍使用方法：
1、xml写文件

如下:

#include <iostream>
#include <rapidxml/rapidxml.hpp>
#include <rapidxml/rapidxml_utils.hpp>
#include <rapidxml/rapidxml_print.hpp>

using namespace rapidxml;

int main()
{    
	xml_document<> doc;  
	xml_node<>* rot = doc.allocate_node(rapidxml::node_pi,doc.allocate_string("xml version='1.0' encoding='utf-8'"));
	doc.append_node(rot);
	xml_node<>* node =   doc.allocate_node(node_element,"config","information");  
	xml_node<>* color =   doc.allocate_node(node_element,"color",NULL);  
	//建议使用如下方法，否则临时变量的指针出了作用域，容易造成xml节点问题
	//std::string s = "color";
	//char* pname = doc.allocate_string(s.c_str());
	//doc.allocate_node(node_element,pname,NULL)
	doc.append_node(node);
	node->append_node(color);
	color->append_node(doc.allocate_node(node_element,"red","0.1"));
	color->append_node(doc.allocate_node(node_element,"green","0.1"));
	color->append_node(doc.allocate_node(node_element,"blue","0.1"));
	color->append_node(doc.allocate_node(node_element,"alpha","1.0"));

	xml_node<>* size =   doc.allocate_node(node_element,"size",NULL); 
	size->append_node(doc.allocate_node(node_element,"x","640"));
	size->append_node(doc.allocate_node(node_element,"y","480"));
	node->append_node(size);

	xml_node<>* mode = doc.allocate_node(rapidxml::node_element,"mode","screen mode");
	mode->append_attribute(doc.allocate_attribute("fullscreen","false"));
	node->append_node(mode);

	std::string text;  
	rapidxml::print(std::back_inserter(text), doc, 0);  

	std::cout<<text<<std::endl; 

	std::ofstream out("config.xml");
	out << doc;

	system("PAUSE");
	return EXIT_SUCCESS;
}

生成的xml文件为:

<?xml version='1.0' encoding='utf-8' ?>
<config>
    <color>
        <red>0.1</red>
        <green>0.1</green>
        <blue>0.1</blue>
        <alpha>1.0</alpha>
    </color>
    <size>
        <x>640</x>
        <y>480</y>
    </size>
    <mode fullscreen="false">screen mode</mode>
</config>

2、读xml文件

#include <iostream>
#include <rapidxml/rapidxml.hpp>
#include <rapidxml/rapidxml_utils.hpp>
#include <rapidxml/rapidxml_print.hpp>

using namespace rapidxml;

int main()
{    
	file<> fdoc("config.xml");
	std::cout<<fdoc.data()<<std::endl; 
	xml_document<>   doc;    
	doc.parse<parse_full>(fdoc.data()); 

	std::cout<<doc.name()<<std::endl;

	//! 获取根节点
	xml_node<>* root = doc.first_node("config");
	std::cout<<root->name()<<std::endl;

	//! 获取根节点第一个节点
	xml_node<>* node1 = root->first_node();
	std::cout<<node1->name()<<std::endl; 

	xml_node<>* node11 = node1->first_node();
	std::cout<<node11->name()<<std::endl;
	std::cout<<node11->value()<<std::endl;

	//! 修改之后再次保存
	xml_node<>* size = root->first_node("size");
	size->append_node(doc.allocate_node(node_element,"w","0"));
	size->append_node(doc.allocate_node(node_element,"h","0"));

	std::string text;  
	rapidxml::print(std::back_inserter(text),doc,0);  

	std::cout<<text<<std::endl; 

	std::ofstream out("config.xml");
	out << doc;

	system("PAUSE");
	return EXIT_SUCCESS;
}

需要说明的是rapidxml明显有一个bug

那就是append_node(doc.allocate_node(node_element,"h","0"));的时候并不考虑该对象是否存在!

转自：http://songhao0201.blog.163.com/blog/static/168027617201131323013399/

ps:对于常量节点名称,值或属性，直接doc.allocate_node(node_element,"color",NULL);没关系，但是有时程序是变量节点，这里要先申请内存：

char* pname = doc.allocate_string(s.c_str());

doc.allocate_node(node_element,pname,NULL)

参考：http://blog.csdn.net/zhaoze87/article/details/7205061
http://www.cppblog.com/tx7do/archive/2010/08/18/123779.html