RapidXml使用方法

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如下

  <?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>

写文件例子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>"//如果单独传, 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();//去顶级结点    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，如果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中不会有xml 头信息---<?xml version='1.0' encoding='utf-8' >    out.close();system("pause");    return 0;}

生成的xml如下

<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;    //! 添加之后再次保存    //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!    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(包括该结点下所有结点)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(); //移除根节点下所有结点text="删除所有节点\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;}

输出信息如下：

<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>删除所有节点<config/>

四、编辑节点信息

暂时找到的编辑方法就是先删除再增加

#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;   }

输出如下：

<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、遍历所有节点

for(rapidxml::xml_node<char> * node = parent_node->first_node("node name");    node != NULL;    node = node->next_sibling()){    ...}

六、遍历所有属性

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，错误信息大概如下

...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()函数被其他函数调用，但在却未定义(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就行。

具体diff文件如下。

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