C++ 使用 tinyxml2 解析创建 xml

1. github 地址

2. 使用

3. 解析xml demo

4. 注意点

5. 解析效果展示

6.创建xml

7.创建xml效果展示

8. 完整的示例，添加Vector

9. 参考

1. github 地址

GitHub - leethomason/tinyxml2: TinyXML2 is a simple, small, efficient, C++ XML parser that can be easily integrated into other programs.

2. 使用

直接把里面的 “tinyxml2.h” 和 “tinyxml2.cpp” 加到自己工程，使用include "tinyxml2.h" 头文件就好

3. 解析xml demo

xml内容如下：

<?xml version="1.0" encoding="utf-8"?>
<annotation><folder>UAV_data</folder><filename>NG0_202303032032377079.xml</filename><size><width>3070</width><height>1600</height><depth>3</depth></size><segmented>0</segmented><object><name>round</name><location>0</location><diffcult>0</diffcult><diffcultt>3</diffcultt><bndbox><xmin>1405</xmin><ymin>1237</ymin><xmax>1628</xmax><ymax>1421</ymax></bndbox></object><object><name>long</name><diffcult>0</diffcult><location>0</location><bndbox><xmin>2337</xmin><ymin>1225</ymin><xmax>2580</xmax><ymax>1405</ymax></bndbox></object>
</annotation>

代码如下：

#include <iostream>
#include"tinyxml2.h"
using namespace std;
using namespace tinyxml2;void decodeXml(std::string xmlPath)
{//声明XMLDocument xml;string value, text;//导入xml文件if (xml.LoadFile(xmlPath.c_str()) != XML_SUCCESS){return;}//判断头文件是否为空XMLElement* rootNode = xml.RootElement();if (rootNode == NULL){return;}XMLElement* surface = rootNode->FirstChildElement("object");while (surface){XMLElement* surfaceChild = surface->FirstChildElement();while (surfaceChild){// surfaceChild->Value() 是获取节点的名称value = surfaceChild->Value();if (value == "bndbox"){XMLElement* bndboxChild = surfaceChild->FirstChildElement();// 因为bndbox节点里面又是节点，所以需要进行循环以及找NextSiblingElementwhile (bndboxChild){value = bndboxChild->Value();text = bndboxChild->GetText();bndboxChild = bndboxChild->NextSiblingElement();std::cout << value << ": " << text << std::endl;}}else{text = surfaceChild->GetText();std::cout << value << ": " << text << std::endl;}surfaceChild = surfaceChild->NextSiblingElement();}surface = surface->NextSiblingElement();}}int main()
{decodeXml("Z:/temp/cppSaveXml/NG0_202303032032377079.xml");return 0;
}

4. 注意点

1. 整体的逻辑其实就是一层一层的遍历，先找到需要遍历的那个节点，然后通过while和NextSiblingElement来进行循环；

2. surfaceChild->Value() 是获取节点的名称，如果 <name>round</name> 得到的是name。这里需要注意的就是，如果节点里面又有节点，这个时候就不能用 surfaceChild->GetText() 来获取里面的值，因为里面是节点，不是单纯的值，如果仍然使用GetText()会报错。
这个时候就需要用FirstChildElement() 这个方法来获取里面第一个节点的内容，然后再通过while进行循环遍历，如下

if (value == "bndbox")
{XMLElement* bndboxChild = surfaceChild->FirstChildElement();// 因为bndbox节点里面又是节点，所以需要进行循环以及找NextSiblingElementwhile (bndboxChild){value = bndboxChild->Value();text = bndboxChild->GetText();bndboxChild = bndboxChild->NextSiblingElement();}
}

3. 总的来说，就是一层一层递归，递归的时候需要判断是否是单节点还是里面还包含节点

5. 解析效果展示

6.创建xml

逻辑就是创建一个根节点，然后再依次创建子节点，然后子节点的 text 属性值设置，然后再把属性值与对应的子节点绑定，然后子节点在与根节点绑定

需要创建如下xml：

<?xml version="1.0" encoding="utf-8"?>
<annotation><filename>NG0_202303032032377079.xml</filename><size><width>3070</width><height>1600</height><depth>3</depth></size><object><name>round</name><bndbox><xmin>1405</xmin><ymin>1237</ymin><xmax>1628</xmax><ymax>1421</ymax></bndbox></object><object><name>long</name><bndbox><xmin>2337</xmin><ymin>1225</ymin><xmax>2580</xmax><ymax>1405</ymax></bndbox></object>
</annotation>

创建代码如下：

XMLElement* getNeedNode(XMLDocument& xml, const char* nodeName, const char* nodeText)
{XMLElement* node = xml.NewElement(nodeName);XMLText* node_text = xml.NewText(nodeText);node->InsertFirstChild(node_text);return node;
}void encode()
{XMLDocument xml;// 插入声明XMLDeclaration* declaration = xml.NewDeclaration();xml.InsertFirstChild(declaration);// 插入根节点XMLElement* rootNode = xml.NewElement("annotation");xml.InsertEndChild(rootNode);/*------------------新建一个filename节点--------------------------*/XMLElement* filename = xml.NewElement("filename");// 设置节点中的值XMLText* filename_text = xml.NewText("NG0_202303032032377079.xml");// 把节点中的值与filename节点链接起来filename->InsertFirstChild(filename_text);// 将 filename 节点与根节点绑定起来rootNode->InsertEndChild(filename);/*------------------新建一个size节点--------------------------*/XMLElement* size = xml.NewElement("size");/*------------------新建一个width节点--------------------------*/XMLElement* width = xml.NewElement("width");XMLText* width_text = xml.NewText("3070");width->InsertFirstChild(width_text);/*------------------新建一个height节点--------------------------*/XMLElement* height = xml.NewElement("height");XMLText* height_text = xml.NewText("1600");height->InsertFirstChild(height_text);/*------------------新建一个depth节点--------------------------*/XMLElement* depth = xml.NewElement("depth");XMLText* depth_text = xml.NewText("3");depth->InsertFirstChild(depth_text);// 将 width,height,depth 与 size 节点绑在一起size->InsertEndChild(width);size->InsertEndChild(height);size->InsertEndChild(depth);/*------------------新建第一个object节点--------------------------*/XMLElement* object = xml.NewElement("object");XMLElement* name = xml.NewElement("name");XMLText* name_text = xml.NewText("round");name->InsertFirstChild(name_text);XMLElement* bndbox = xml.NewElement("bndbox");// getNeedNode 方法为啥是引用，因为是要同一个 XMLDocument 这样才可以绑定， 所以传引用XMLElement* xmin = getNeedNode(xml, "xmin", "1405");XMLElement* ymin = getNeedNode(xml, "ymin", "1237");XMLElement* xmax = getNeedNode(xml, "xmax", "1628");XMLElement* ymax = getNeedNode(xml, "ymax", "1421");bndbox->InsertEndChild(xmin);bndbox->InsertEndChild(ymin);bndbox->InsertEndChild(xmax);bndbox->InsertEndChild(ymax);object->InsertEndChild(name);object->InsertEndChild(bndbox);rootNode->InsertEndChild(object);/*------------------新建第二个object节点--------------------------*/object = xml.NewElement("object");name = xml.NewElement("name");name_text = xml.NewText("long");name->InsertFirstChild(name_text);bndbox = xml.NewElement("bndbox");xmin = getNeedNode(xml, "xmin", "2337");ymin = getNeedNode(xml, "ymin", "1225");xmax = getNeedNode(xml, "xmax", "2580");ymax = getNeedNode(xml, "ymax", "1405");bndbox->InsertEndChild(xmin);bndbox->InsertEndChild(ymin);bndbox->InsertEndChild(xmax);bndbox->InsertEndChild(ymax);object->InsertEndChild(name);object->InsertEndChild(bndbox);rootNode->InsertEndChild(object);xml.SaveFile("Z:/temp/cppSaveXml/temp.xml");}int main()
{encode();return 0;
}

7.创建xml效果展示

8. 完整的示例，添加Vector

生成xml，使用传入vector，然后循环遍历vector

#include <iostream>
#include <vector>
#include <string>
#include"tinyxml2.h"
//#include "xmlNode.h"using namespace tinyxml2;struct Node
{int imageW;int imageH;int channel = 3;int xmin;int ymin;int xmax;int ymax;std::string label;float prob;Node(int in_w, int in_h, int in_xmin, int in_ymin, int in_xmax, int in_ymax, std::string in_label, float in_prob){imageW = in_w;imageH = in_h;xmin = in_xmin;ymin = in_ymin;;xmax = in_xmax;;ymax = in_ymax;;label = in_label;;prob = in_prob;;}
};void decodeXml(std::string xmlPath)
{//声明XMLDocument xml;std::string value, text;//导入xml文件if (xml.LoadFile(xmlPath.c_str()) != XML_SUCCESS){return;}//判断头文件是否为空XMLElement* rootNode = xml.RootElement();if (rootNode == NULL){return;}XMLElement* filename = rootNode->FirstChildElement("filename");const char* getFileName = filename->GetText();std::cout << getFileName << std::endl;XMLElement* surface = rootNode->FirstChildElement("object");while (surface){XMLElement* surfaceChild = surface->FirstChildElement();while (surfaceChild){// surfaceChild->Value() 是获取节点的名称value = surfaceChild->Value();if (value == "bndbox"){XMLElement* bndboxChild = surfaceChild->FirstChildElement();// 因为bndbox节点里面又是节点，所以需要进行循环以及找NextSiblingElementwhile (bndboxChild){value = bndboxChild->Value();text = bndboxChild->GetText();bndboxChild = bndboxChild->NextSiblingElement();std::cout << value << ": " << text << std::endl;}}else{text = surfaceChild->GetText();std::cout << value << ": " << text << std::endl;}surfaceChild = surfaceChild->NextSiblingElement();}surface = surface->NextSiblingElement();}}XMLElement* getNeedNode(XMLDocument& xml, const char* nodeName, const char* nodeText)
{XMLElement* node = xml.NewElement(nodeName);XMLText* node_text = xml.NewText(nodeText);node->InsertFirstChild(node_text);return node;
}void encodeXml(const char* inSaveXmlDir, int inW, int inH, std::vector<Node> inAllNode)
{XMLDocument xml;// 插入声明XMLDeclaration* declaration = xml.NewDeclaration();xml.InsertFirstChild(declaration);// 插入根节点XMLElement* rootNode = xml.NewElement("annotation");xml.InsertEndChild(rootNode);/*------------------新建一个filename节点--------------------------*/XMLElement* filename = xml.NewElement("filename");// 设置节点中的值XMLText* filename_text = xml.NewText(inSaveXmlDir);// 把节点中的值与filename节点链接起来filename->InsertFirstChild(filename_text);// 将 filename 节点与根节点绑定起来rootNode->InsertEndChild(filename);/*------------------新建一个size节点--------------------------*/XMLElement* size = xml.NewElement("size");/*------------------新建一个width节点--------------------------*/XMLElement* width = xml.NewElement("width");XMLText* width_text = xml.NewText(std::to_string(inW).c_str());width->InsertFirstChild(width_text);/*------------------新建一个height节点--------------------------*/XMLElement* height = xml.NewElement("height");XMLText* height_text = xml.NewText(std::to_string(inH).c_str());height->InsertFirstChild(height_text);/*------------------新建一个depth节点--------------------------*/XMLElement* depth = xml.NewElement("depth");XMLText* depth_text = xml.NewText("3");depth->InsertFirstChild(depth_text);// 将 width,height,depth 与 size 节点绑在一起size->InsertEndChild(width);size->InsertEndChild(height);size->InsertEndChild(depth);rootNode->InsertEndChild(filename);rootNode->InsertEndChild(size);/*------------------新建第一个object节点--------------------------*/for (auto node : inAllNode){XMLElement* object = xml.NewElement("object");XMLElement* name = xml.NewElement("name");XMLText* name_text = xml.NewText(node.label.c_str());name->InsertFirstChild(name_text);XMLElement* bndbox = xml.NewElement("bndbox");// getNeedNode 方法为啥是引用，因为是要同一个 XMLDocument 这样才可以绑定， 所以传引用XMLElement* xmin = getNeedNode(xml, "xmin", std::to_string(node.xmin).c_str());XMLElement* ymin = getNeedNode(xml, "ymin", std::to_string(node.ymin).c_str());XMLElement* xmax = getNeedNode(xml, "xmax", std::to_string(node.xmax).c_str());XMLElement* ymax = getNeedNode(xml, "ymax", std::to_string(node.ymax).c_str());bndbox->InsertEndChild(xmin);bndbox->InsertEndChild(ymin);bndbox->InsertEndChild(xmax);bndbox->InsertEndChild(ymax);object->InsertEndChild(name);object->InsertEndChild(bndbox);rootNode->InsertEndChild(object);}xml.SaveFile(inSaveXmlDir);}int main()
{const char* saveXmlDir = "Z:/temp/cppSaveXml/1.xml";std::vector<Node> allNode;Node nodeOne = { 1, 2, 3, 4, 5, 6, "1", 0.1 };Node nodeTwo = { 1, 2, 3, 4, 5, 6, "2", 0.1 };allNode.push_back(nodeOne);allNode.push_back(nodeTwo);encodeXml(saveXmlDir, 3070, 1600, allNode);return 0;
}

效果展示

9. 参考

1. C++解析XML文件_c++ xml解析_时·风·人的博客-CSDN博客