RapidXml使用方法

一、写xml 文件

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1. #include <iostream>
2. #include "rapidxml/rapidxml.hpp"
3. #include "rapidxml/rapidxml_utils.hpp"
4. #include "rapidxml/rapidxml_print.hpp"
5. using namespace rapidxml;
6. int main()
7. {
8. xml_document<> doc;
9. xml_node<>* rot = doc.allocate_node(rapidxml::node_pi,doc.allocate_string("xml version='1.0' encoding='utf-8'"));
10. doc.append_node(rot);
11. xml_node<>* node =   doc.allocate_node(node_element,"config","information");
12. xml_node<>* color =   doc.allocate_node(node_element,"color",NULL);
13. doc.append_node(node);
14. node->append_node(color);
15. color->append_node(doc.allocate_node(node_element,"red","0.1"));
16. color->append_node(doc.allocate_node(node_element,"green","0.1"));
17. color->append_node(doc.allocate_node(node_element,"blue","0.1"));
18. color->append_node(doc.allocate_node(node_element,"alpha","1.0"));
19. xml_node<>* size =   doc.allocate_node(node_element,"size",NULL);
20. size->append_node(doc.allocate_node(node_element,"x","640"));
21. size->append_node(doc.allocate_node(node_element,"y","480"));
22. node->append_node(size);
23. xml_node<>* mode = doc.allocate_node(rapidxml::node_element,"mode","screen mode");
24. mode->append_attribute(doc.allocate_attribute("fullscreen","false"));
25. node->append_node(mode);
26. std::string text;
27. rapidxml::print(std::back_inserter(text), doc, 0);
28. std::cout<<text<<std::endl;
29. std::ofstream out("config.xml");
30. out << doc;
31. system("PAUSE");
32. return EXIT_SUCCESS;
33. }

生成的xml如下

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1. <?xml version="1.0" encoding="utf-8" ?>
2. - <config>
3. - <color>
4. <red>0.1</red>
5. <green>0.1</green>
6. <blue>0.1</blue>
7. <alpha>1.0</alpha>
8. </color>
9. - <size>
10. <x>640</x>
11. <y>480</y>
12. </size>
13. <mode fullscreen="false">screen mode</mode>
14. </config>

写文件例子2：

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1. #include <string>
2. #include <iostream>
3. #include <fstream>
4. #include "rapidxml/rapidxml.hpp"
5. #include "rapidxml/rapidxml_utils.hpp"
6. #include "rapidxml/rapidxml_print.hpp"
7. using namespace rapidxml;
8. using namespace std;
9. int main(int argc, char* argv[])
10. {
11. xml_document<> doc; //是解析器
12. char a[] = "<top>"//如果单独传, 就不能加上xml的头部信息，
13. //否则会报错
14. "<name>tangqiang</name>"
15. "<age>22</age>"
16. "</top>";
17. char* p = a;
18. doc.parse<0>(p);
19. xml_node<>* node = doc.first_node();//去顶级结点
20. cout << (node->name())<< endl;
21. node = node->first_node();
22. while (node) {
23. 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
24. node = node->next_sibling();
25. }
26. 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
27. 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' >
28. out.close();
29. system("pause");
30. return 0;
31. }

生成的xml如下

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1. <top>
2. <name>tangqiang</name>
3. <age>22</age>
4. </top>

二、读取xml文件

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1. #include <iostream>
2. #include "rapidxml/rapidxml.hpp"
3. #include "rapidxml/rapidxml_utils.hpp"
4. #include "rapidxml/rapidxml_print.hpp"
5. using namespace rapidxml;
6. int main()
7. {
8. file<> fdoc("config.xml");
9. std::cout<<fdoc.data()<<std::endl;
10. xml_document<>   doc;
11. doc.parse<0>(fdoc.data());
12. std::cout<<doc.name()<<std::endl;
13. //! 获取根节点
14. xml_node<>* root = doc.first_node();
15. std::cout<<root->name()<<std::endl;
16. //! 获取根节点第一个节点
17. xml_node<>* node1 = root->first_node();
18. std::cout<<node1->name()<<std::endl;
19. xml_node<>* node11 = node1->first_node();
20. std::cout<<node11->name()<<std::endl;
21. std::cout<<node11->value()<<std::endl;
22. //! 添加之后再次保存
23. //需要说明的是rapidxml明显有一个bug
24. //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!
25. xml_node<>* size = root->first_node("size");
26. size->append_node(doc.allocate_node(node_element,"w","0"));
27. size->append_node(doc.allocate_node(node_element,"h","0"));
28. std::string text;
29. rapidxml::print(std::back_inserter(text),doc,0);
30. std::cout<<text<<std::endl;
31. std::ofstream out("config.xml");
32. out << doc;
33. system("PAUSE");
34. return EXIT_SUCCESS;
35. }

生成的xml为

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1. <config>
2. <color>
3. <red>0.1</red>
4. <green>0.1</green>
5. <blue>0.1</blue>
6. <alpha>1.0</alpha>
7. </color>
8. <size>
9. <x>640</x>
10. <y>480</y>
11. <w>0</w>
12. <h>0</h>
13. </size>
14. <mode fullscreen="false">screen mode</mode>
15. </config>

三、删除节点

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1. #include "rapidxml/rapidxml.hpp"
2. #include "rapidxml/rapidxml_utils.hpp"
3. #include "rapidxml/rapidxml_print.hpp"
4. #include<iostream>
5. using namespace rapidxml;
6. int main()
7. {
8. file<> fdoc("config.xml");
9. xml_document<> doc;
10. doc.parse<0>(fdoc.data());
11. std::string text;
12. rapidxml::print(std::back_inserter(text), doc, 0);
13. std::cout<<text<<std::endl;
14. xml_node<>* root = doc.first_node();
15. xml_node<>* sec = root->first_node();
16. root->remove_node(sec); //移除根节点下的sec结点(包括该结点下所有结点)
17. text="删除一个节点\r\n";
18. rapidxml::print(std::back_inserter(text), doc, 0);
19. std::cout<<text<<std::endl;
20. root->remove_all_nodes(); //移除根节点下所有结点
21. text="删除所有节点\r\n";
22. rapidxml::print(std::back_inserter(text), doc, 0);
23. std::cout<<text<<std::endl;
24. std::ofstream out("test.xml");
25. out<<doc;
26. system("pause");
27. return 0;
28. }

输出信息如下：

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1. <config>
2. <color>
3. <red>0.1</red>
4. <green>0.1</green>
5. <blue>0.1</blue>
6. <alpha>1.0</alpha>
7. </color>
8. <size>
9. <x>640</x>
10. <y>480</y>
11. <w>0</w>
12. <h>0</h>
13. </size>
14. <mode fullscreen="false">screen mode</mode>
15. </config>
16. 删除一个节点
17. <config>
18. <size>
19. <x>640</x>
20. <y>480</y>
21. <w>0</w>
22. <h>0</h>
23. </size>
24. <mode fullscreen="false">screen mode</mode>
25. </config>
26. 删除所有节点
27. <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

[cpp] view plaincopy

1. #include "rapidxml/rapidxml.hpp"
2. #include "rapidxml/rapidxml_utils.hpp"
3. #include "rapidxml/rapidxml_print.hpp"
4. #include<iostream>
5. using namespace rapidxml;
6. int main()
7. {
8. file<> fdoc("config.xml");
9. std::cout<<fdoc.data()<<std::endl;
10. xml_document<> doc;
11. doc.parse<0>(fdoc.data());
12. std::cout<<doc.name()<<std::endl;
13. //! 获取根节点
14. xml_node<>* root = doc.first_node();
15. xml_node<>* delnode = root->first_node("color");
16. root->remove_node(delnode);//先删除address节点
17. //
18. xml_node<>* lnode = root->first_node("size");//找到post节点
19. xml_node<>* mynode=doc.allocate_node(node_element,"address","河北");
20. root->insert_node(lnode,mynode);
21. std::string text;
22. rapidxml::print(std::back_inserter(text),doc,0);
23. std::cout<<text<<std::endl;
24. std::ofstream out("version.xml");
25. out << doc;
26. system("pause");
27. return 0;
28. }

输出如下：

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1. <config>
2. <color>
3. <red>0.1</red>
4. <green>0.1</green>
5. <blue>0.1</blue>
6. <alpha>1.0</alpha>
7. </color>
8. <size>
9. <x>640</x>
10. <y>480</y>
11. <w>0</w>
12. <h>0</h>
13. </size>
14. <mode fullscreen="false">screen mode</mode>
15. </config>
16. <config>
17. <address>河北</address>
18. <size>
19. <x>640</x>
20. <y>480</y>
21. <w>0</w>
22. <h>0</h>
23. </size>
24. <mode fullscreen="false">screen mode</mode>
25. </config>

五、遍历所有节点

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1. for(rapidxml::xml_node<char> * node = parent_node->first_node("node name");
2. node != NULL;
3. node = node->next_sibling())
4. {
5. ...
6. }

六、遍历所有属性

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1. for(rapidxml::xml_attribute<char> * attr = node->first_attribute("node name");
2. attr != NULL;
3. attr = attr->next_attribute())
4. {
5. char * value = attr->value();
6. }

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。

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