RapidXml用法

2023-03-13 09:11:42

一、写xml 文件

#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);

	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例如以下

  <?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>

写文件样例2：

#include <string>

#include <iostream>

#include <fstream>

#include "rapidxml/rapidxml.hpp"

#include "rapidxml/rapidxml_utils.hpp"

#include "rapidxml/rapidxml_print.hpp"

using namespace rapidxml;

using namespace std;

int main(int argc, char* argv[])

{

    xml_document<> doc; //是解析器

    char a[] = "<top>"//假设单独传, 就不能加上xml的头部信息，

               //否则会报错

               "<name>tangqiang</name>"

               "<age>22</age>"

               "</top>";

    char* p = a;

    doc.parse<0>(p);

    xml_node<>* node = doc.first_node();//去*结点

    cout << (node->name())<< endl;

    node = node->first_node();

    while (node) {

        cout << node->name() << node->value() << endl;//name() value()返回的字符串不会去掉首尾的空白字符

        node = node->next_sibling();

    }

    ofstream out("test.xml");//ofstream 默认时，假设文件存在则会覆盖原来的内容，不存在则会新建

    out << doc;//doc 这样输出时在目标文件里不会有xml 头信息---<?xml version='1.0' encoding='utf-8' >

    out.close();

	system("pause");

    return 0;

}

生成的xml例如以下

<top>

	<name>tangqiang</name>

	<age>22</age>

</top>

二、读取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<0>(fdoc.data());

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

    //! 获取根节点

    xml_node<>* root = doc.first_node();

    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;

    //! 加入�之后再次保存

    //须要说明的是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!

    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;

}

生成的xml为

<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>

		<w>0</w>

		<h>0</h>

	</size>

	<mode fullscreen="false">screen mode</mode>

</config>

三、删除节点

#include "rapidxml/rapidxml.hpp"

#include "rapidxml/rapidxml_utils.hpp"

#include "rapidxml/rapidxml_print.hpp"

#include<iostream>

using namespace rapidxml;

int main()

{

	file<> fdoc("config.xml");

	xml_document<> doc;

	doc.parse<0>(fdoc.data());

	std::string text;

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

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

	xml_node<>* root = doc.first_node();

	xml_node<>* sec = root->first_node();

	root->remove_node(sec); //移除根节点下的sec结点(包含该结点下全部结点)

	text="删除一个节点\r\n";

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

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

	root->remove_all_nodes(); //移除根节点下全部结点

	text="删除全部节点\r\n";

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

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

	std::ofstream out("test.xml");

	out<<doc;

	system("pause");

	return 0;

}

输出信息例如以下：

<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>

		<w>0</w>

		<h>0</h>

	</size>

	<mode fullscreen="false">screen mode</mode>

</config>

删除一个节点

<config>

	<size>

		<x>640</x>

		<y>480</y>

		<w>0</w>

		<h>0</h>

	</size>

	<mode fullscreen="false">screen mode</mode>

</config>

删除全部节点

<config/>

四、编辑节点信息

临时找到的编辑方法就是先删除再添加�

#include "rapidxml/rapidxml.hpp"

#include "rapidxml/rapidxml_utils.hpp"

#include "rapidxml/rapidxml_print.hpp"

#include<iostream>

using namespace rapidxml;

int main()

{

	file<> fdoc("config.xml");

	std::cout<<fdoc.data()<<std::endl;

	xml_document<> doc;

	doc.parse<0>(fdoc.data());

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

	//! 获取根节点

	xml_node<>* root = doc.first_node();

	xml_node<>* delnode = root->first_node("color");

	root->remove_node(delnode);//先删除address节点

	//

	xml_node<>* lnode = root->first_node("size");//找到post节点

	xml_node<>* mynode=doc.allocate_node(node_element,"address","河北");

	root->insert_node(lnode,mynode);

	std::string text;

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

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

	std::ofstream out("version.xml");

	out << doc;

	system("pause");

	return 0;

}

输出例如以下：

<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>

		<w>0</w>

		<h>0</h>

	</size>

	<mode fullscreen="false">screen mode</mode>

</config>

<config>

	<address>河北</address>

	<size>

		<x>640</x>

		<y>480</y>

		<w>0</w>

		<h>0</h>

	</size>

	<mode fullscreen="false">screen mode</mode>

</config>

五、遍历全部节点

for(rapidxml::xml_node<char> * node = parent_node->first_node("node name");

    node != NULL;

    node = node->next_sibling())

{

    ...

}

六、遍历全部属性

for(rapidxml::xml_attribute<char> * attr = node->first_attribute("node name");

    attr != NULL;

    attr = attr->next_attribute())

{

    char * value = attr->value();

}

七、gcc使用-std=gnu++0x 编译rapidxml时会报错，错误信息大概例如以下

...rapidxml_print.hpp:120:23: error:

call to function 'print_element_node' thatis neither visible in the

template definition nor found byargument-dependent lookup

out = print_element_node(out, node, flags,indent);

^

...rapidxml_print.hpp:242:22: note:

'print_element_node' should be declaredprior to the call site or in

namespace 'rapidxml'

inline OutIt print_element_node(OutIt out,const xml_node<Ch> ...

在这里找到了解决方法。

经查，原来print_node()函数被其它函数调用，但在却没有定义(在被调用函数后定义了)，所以解决方法为把print_node()函数移到print_children(), print_element_node() 等函数的后面。在原定义处就留一个函数声明即可。

详细diff文件例如以下。

Index: rapidxml_print.hpp

===================================================================

--- rapidxml_print.hpp	(revision 2025)

+++ rapidxml_print.hpp	(revision 2080)

@@ -101,68 +101,9 @@

         ///////////////////////////////////////////////////////////////////////////

         // Internal printing operations

-

-        // Print node

+

         template<class OutIt, class Ch>

-        inline OutIt print_node(OutIt out, const xml_node<Ch> *node, int flags, int indent)

-        {

-            // Print proper node type

-            switch (node->type())

-            {

-

-            // Document

-            case node_document:

-                out = print_children(out, node, flags, indent);

-                break;

-

-            // Element

-            case node_element:

-                out = print_element_node(out, node, flags, indent);

-                break;

-

-            // Data

-            case node_data:

-                out = print_data_node(out, node, flags, indent);

-                break;

-

-            // CDATA

-            case node_cdata:

-                out = print_cdata_node(out, node, flags, indent);

-                break;

-

-            // Declaration

-            case node_declaration:

-                out = print_declaration_node(out, node, flags, indent);

-                break;

-

-            // Comment

-            case node_comment:

-                out = print_comment_node(out, node, flags, indent);

-                break;

-

-            // Doctype

-            case node_doctype:

-                out = print_doctype_node(out, node, flags, indent);

-                break;

-

-            // Pi

-            case node_pi:

-                out = print_pi_node(out, node, flags, indent);

-                break;

-

-                // Unknown

-            default:

-                assert(0);

-                break;

-            }

-

-            // If indenting not disabled, add line break after node

-            if (!(flags & print_no_indenting))

-                *out = Ch('\n'), ++out;

-

-            // Return modified iterator

-            return out;

-        }

+        inline OutIt print_node(OutIt out, const xml_node<Ch> *node, int flags, int indent);        

         // Print children of the node

         template<class OutIt, class Ch>

@@ -372,7 +313,69 @@

             *out = Ch('>'), ++out;

             return out;

         }

+

+        // Print node

+        template<class OutIt, class Ch>

+        inline OutIt print_node(OutIt out, const xml_node<Ch> *node, int flags, int indent)

+        {

+            // Print proper node type

+            switch (node->type())

+            {

+            // Document

+            case node_document:

+                out = print_children(out, node, flags, indent);

+                break;

+

+            // Element

+            case node_element:

+                out = print_element_node(out, node, flags, indent);

+                break;

+

+            // Data

+            case node_data:

+                out = print_data_node(out, node, flags, indent);

+                break;

+

+            // CDATA

+            case node_cdata:

+                out = print_cdata_node(out, node, flags, indent);

+                break;

+

+            // Declaration

+            case node_declaration:

+                out = print_declaration_node(out, node, flags, indent);

+                break;

+

+            // Comment

+            case node_comment:

+                out = print_comment_node(out, node, flags, indent);

+                break;

+

+            // Doctype

+            case node_doctype:

+                out = print_doctype_node(out, node, flags, indent);

+                break;

+

+            // Pi

+            case node_pi:

+                out = print_pi_node(out, node, flags, indent);

+                break;

+

+                // Unknown

+            default:

+                assert(0);

+                break;

+            }

+

+            // If indenting not disabled, add line break after node

+            if (!(flags & print_no_indenting))

+                *out = Ch('\n'), ++out;

+

+            // Return modified iterator

+            return out;

+        }

+

     }

     //! \endcond
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