C++操作XML之二---RapidXml

rapidxml是一个快速的xml库，官方网站：  http://rapidxml.sourceforge.net/，根据manual看到，他竟然比tinyxml快了50-100倍

下载解压以后，把以下三个头文件#include引入

rapidxml.hpp

rapidxml_utils.hpp

rapidxml_print.hpp

#include
#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<

    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>0.1red>
  <green>0.1green>
  <blue>0.1blue>
  <alpha>1.0alpha>
  color>
- <size>
  <x>640x>
  <y>480y>
  size>
  <mode fullscreen="false">screen modemode>
  config>

写文件例子2：

#include
#include
#include
#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[] = ""//如果单独传, 就不能加上xml的头部信息，
               //否则会报错
               "tangqiang"
               "22"
               "";
    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---
    out.close();
    system("pause");
    return 0;
}

生成的xml如下

<top>
    <name>tangqiangname>
    <age>22age>
top>

二、读取xml文件

#include
#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<
    xml_document<>   doc;
    doc.parse<0>(fdoc.data());

    std::cout<

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

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

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

    //! 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<

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

    system("PAUSE");
    return EXIT_SUCCESS;
}

生成的xml为

<config>
    <color>
        <red>0.1red>
        <green>0.1green>
        <blue>0.1blue>
        <alpha>1.0alpha>
    color>
    <size>
        <x>640x>
        <y>480y>
        <w>0w>
        <h>0h>
    size>
    <mode fullscreen="false">screen modemode>
config>

三、删除节点

#include "rapidxml/rapidxml.hpp"
#include "rapidxml/rapidxml_utils.hpp"
#include "rapidxml/rapidxml_print.hpp"

#include
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<

    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<

    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<

    std::ofstream out("test.xml");
    out<
    system("pause");
    return 0;
}

输出信息如下：

<config>
    <color>
        <red>0.1red>
        <green>0.1green>
        <blue>0.1blue>
        <alpha>1.0alpha>
    color>
    <size>
        <x>640x>
        <y>480y>
        <w>0w>
        <h>0h>
    size>
    <mode fullscreen="false">screen modemode>
config>


删除一个节点

<config>
    <size>
        <x>640x>
        <y>480y>
        <w>0w>
        <h>0h>
    size>
    <mode fullscreen="false">screen modemode>
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
using namespace rapidxml;

int main()
{
    file<> fdoc("config.xml");
    std::cout<
    xml_document<> doc;
    doc.parse<0>(fdoc.data());

    std::cout<

    //! 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<

    std::ofstream out("version.xml");
    out << doc;
    system("pause");
    return 0;
}

输出如下：

<config>

    <color>

        <red>0.1red>

        <green>0.1green>

        <blue>0.1blue>

        <alpha>1.0alpha>

    color>

    <size>

        <x>640x>

        <y>480y>

        <w>0w>

        <h>0h>

    size>

    <mode fullscreen="false">screen modemode>

config>





<config>
    <address>河北address>
    <size>
        <x>640x>
        <y>480y>
        <w>0w>
        <h>0h>
    size>
    <mode fullscreen="false">screen modemode>
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 ...

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。

[plain] view plain copy

1. Index: rapidxml_print.hpp  
2. ===================================================================  
3. --- rapidxml_print.hpp  (revision 2025)  
4. +++ rapidxml_print.hpp  (revision 2080)  
5. @@ -101,68 +101,9 @@  
6.    
7.          ///  
8.          // Internal printing operations  
9. -      
10. -        // Print node  
11. +          
12.          template  
13. -        inline OutIt print_node(OutIt out, const xml_node *node, int flags, int indent)  
14. -        {  
15. -            // Print proper node type  
16. -            switch (node->type())  
17. -            {  
18. -  
19. -            // Document  
20. -            case node_document:  
21. -                out = print_children(out, node, flags, indent);  
22. -                break;  
23. -  
24. -            // Element  
25. -            case node_element:  
26. -                out = print_element_node(out, node, flags, indent);  
27. -                break;  
28. -              
29. -            // Data  
30. -            case node_data:  
31. -                out = print_data_node(out, node, flags, indent);  
32. -                break;  
33. -              
34. -            // CDATA  
35. -            case node_cdata:  
36. -                out = print_cdata_node(out, node, flags, indent);  
37. -                break;  
38. -  
39. -            // Declaration  
40. -            case node_declaration:  
41. -                out = print_declaration_node(out, node, flags, indent);  
42. -                break;  
43. -  
44. -            // Comment  
45. -            case node_comment:  
46. -                out = print_comment_node(out, node, flags, indent);  
47. -                break;  
48. -              
49. -            // Doctype  
50. -            case node_doctype:  
51. -                out = print_doctype_node(out, node, flags, indent);  
52. -                break;  
53. -  
54. -            // Pi  
55. -            case node_pi:  
56. -                out = print_pi_node(out, node, flags, indent);  
57. -                break;  
58. -  
59. -                // Unknown  
60. -            default:  
61. -                assert(0);  
62. -                break;  
63. -            }  
64. -              
65. -            // If indenting not disabled, add line break after node  
66. -            if (!(flags & print_no_indenting))  
67. -                *out = Ch('\n'), ++out;  
68. -  
69. -            // Return modified iterator  
70. -            return out;  
71. -        }  
72. +        inline OutIt print_node(OutIt out, const xml_node *node, int flags, int indent);          
73.            
74.          // Print children of the node                                 
75.          template  
76. @@ -372,7 +313,69 @@  
77.              *out = Ch('>'), ++out;  
78.              return out;  
79.          }  
80. +          
81. +        // Print node  
82. +        template  
83. +        inline OutIt print_node(OutIt out, const xml_node *node, int flags, int indent)  
84. +        {  
85. +            // Print proper node type  
86. +            switch (node->type())  
87. +            {  
88.    
89. +            // Document  
90. +            case node_document:  
91. +                out = print_children(out, node, flags, indent);  
92. +                break;  
93. +  
94. +            // Element  
95. +            case node_element:  
96. +                out = print_element_node(out, node, flags, indent);  
97. +                break;  
98. +              
99. +            // Data  
100. +            case node_data:  
101. +                out = print_data_node(out, node, flags, indent);  
102. +                break;  
103. +              
104. +            // CDATA  
105. +            case node_cdata:  
106. +                out = print_cdata_node(out, node, flags, indent);  
107. +                break;  
108. +  
109. +            // Declaration  
110. +            case node_declaration:  
111. +                out = print_declaration_node(out, node, flags, indent);  
112. +                break;  
113. +  
114. +            // Comment  
115. +            case node_comment:  
116. +                out = print_comment_node(out, node, flags, indent);  
117. +                break;  
118. +              
119. +            // Doctype  
120. +            case node_doctype:  
121. +                out = print_doctype_node(out, node, flags, indent);  
122. +                break;  
123. +  
124. +            // Pi  
125. +            case node_pi:  
126. +                out = print_pi_node(out, node, flags, indent);  
127. +                break;  
128. +  
129. +                // Unknown  
130. +            default:  
131. +                assert(0);  
132. +                break;  
133. +            }  
134. +              
135. +            // If indenting not disabled, add line break after node  
136. +            if (!(flags & print_no_indenting))  
137. +                *out = Ch('\n'), ++out;  
138. +  
139. +            // Return modified iterator  
140. +            return out;  
141. +        }          
142. +  
143.      }  
144.      //! \endcond 
     

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