开源库TinyXML2简介及使用

TinyXML2是一个开源、简单、小巧、高效的C++ XML解析器，它只有一个.h文件和一个.cpp文件组成，可以轻松集成到其它程序中。它解析XML文档并从中构建可以读取、修改和保存的文档对象模型(Document Object Model, DOM)。它不能解析DTD(Document Type Definitions, 文档类型定义)或XSL(eXtensible Stylesheet Language, 扩展样式表语言)。在TinyXML2中，XML数据被解析为可以浏览和操作的C++对象，然后写入磁盘和其它输出流。它不依赖于C++的STL。

TinyXML2的license为ZLib，可以商用，它的源码在https://github.com/leethomason/tinyxml2 ，最新发布版本为7.1.0。

关于XML的介绍可以参考：https://blog.csdn.net/fengbingchun/article/details/38978591

以下是测试代码(test_tinyxml2.cpp)：创建XML(test_tinyxml2_create)和解析XML(test_tinyxml2_parse)

#include "funset.hpp"
#include <iostream>
#include "tinyxml2.h"

int test_tinyxml2_create()
{
	const char* declaration = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>";
	tinyxml2::XMLDocument doc;
	tinyxml2::XMLError ret = doc.Parse(declaration);
	if (ret != 0) {
		fprintf(stderr, "fail to parse xml file: %s\n", declaration);
		return -1;
	}

	tinyxml2::XMLComment* comment = doc.NewComment("this is a xml test file");
	doc.InsertEndChild(comment);

	tinyxml2::XMLElement* root = doc.NewElement("Root");
	doc.InsertEndChild(root);

	// User
	tinyxml2::XMLElement* user = doc.NewElement("User");
	user->SetAttribute("Name", "fengbingchun");
	root->InsertEndChild(user);

	tinyxml2::XMLElement* blog = doc.NewElement("Blog");
	tinyxml2::XMLText* text1 = doc.NewText("CSDN");
	blog->InsertEndChild(text1);
	user->InsertEndChild(blog);
	
	tinyxml2::XMLElement* code = doc.NewElement("Code");
	tinyxml2::XMLText* text2 = doc.NewText("GitHub");
	code->InsertEndChild(text2);
	user->InsertEndChild(code);
	
	// Blog
	tinyxml2::XMLElement* blog2 = doc.NewElement("Blog");
	blog2->SetAttribute("Name", "CSDN");
	root->InsertEndChild(blog2);

	tinyxml2::XMLElement* addr = doc.NewElement("Address");
	tinyxml2::XMLText* text3 = doc.NewText("https://blog.csdn.net/fengbingchun");
	addr->InsertEndChild(text3);
	blog2->InsertEndChild(addr);
	
	tinyxml2::XMLElement* id = doc.NewElement("ID");
	tinyxml2::XMLText* text4 = doc.NewText("fengbingchun");
	id->InsertEndChild(text4);
	blog2->InsertEndChild(id);

	// Code
	tinyxml2::XMLElement* code2 = doc.NewElement("Code");
	code2->SetAttribute("Name", "GitHub");
	root->InsertEndChild(code2);

	tinyxml2::XMLElement* addr2 = doc.NewElement("Address");
	tinyxml2::XMLText* text5 = doc.NewText("https://github.com//fengbingchun");
	addr2->InsertEndChild(text5);
	code2->InsertEndChild(addr2);
	
	tinyxml2::XMLElement* repositories = doc.NewElement("Repositories");
	tinyxml2::XMLText* text6 = doc.NewText("27");
	repositories->InsertEndChild(text6);
	code2->InsertEndChild(repositories);

#ifdef _MSC_VER
	const char* file_name = "E:/GitCode/Messy_Test/testdata/test.xml"; 
#else
	const char* file_name = "testdata/test.xml";
#endif

	ret = doc.SaveFile(file_name);
	if (ret != 0) {
		fprintf(stderr, "fail to save xml file: %s\n", file_name);
		return -1;
	}

	return 0;
}

int test_tinyxml2_parse()
{
#ifdef _MSC_VER
	const char* file_name = "E:/GitCode/Messy_Test/testdata/test_tinyxml2.xml"; 
#else
	const char* file_name = "testdata/test_tinyxml2.xml";
#endif

	tinyxml2::XMLDocument doc;
	tinyxml2::XMLError ret = doc.LoadFile(file_name);
	if (ret != 0) {
		fprintf(stderr, "fail to load xml file: %s\n", file_name);
		return -1;
	}

	tinyxml2::XMLElement* root = doc.RootElement();
	fprintf(stdout, "root element name: %s\n", root->Name());

	// User
	tinyxml2::XMLElement* user = root->FirstChildElement("User");
	if (!user) {
		fprintf(stderr, "no child element: User\n");
		return -1;
	}
	fprintf(stdout, "user name: %s\n", user->Attribute("Name"));

	tinyxml2::XMLElement* blog = user->FirstChildElement("Blog");
	if (!blog) {
		fprintf(stderr, "no child element: Blog, in User\n");
		return -1;
	}
	fprintf(stdout, "blog value: %s\n", blog->GetText());
	fprintf(stdout, "code value: %s\n\n", user->FirstChildElement("Code")->GetText());
	
	// Blog
	tinyxml2::XMLElement* blog2 = root->FirstChildElement("Blog");
	if (!blog2) {
		fprintf(stderr, "no child element: Blog\n");
		return -1;
	}
	fprintf(stdout, "blog name: %s\n", blog2->Attribute("Name"));

	tinyxml2::XMLElement* addr = blog2->FirstChildElement("Address");
	if (!addr) {
		fprintf(stderr, "no child element: Address, in Blog\n");
		return -1;
	}
	fprintf(stdout, "address value: %s\n", addr->GetText());
	fprintf(stdout, "id value: %s\n\n", blog2->FirstChildElement("ID")->GetText());
	
	// Code
	tinyxml2::XMLElement* code = root->FirstChildElement("Code");
	if (!code) {
		fprintf(stderr, "no child element: Code\n");
		return -1;
	}
	fprintf(stdout, "code name: %s\n", code->Attribute("Name"));

	tinyxml2::XMLElement* addr2 = code->FirstChildElement("Address");
	if (!addr2) {
		fprintf(stderr, "no child element: Address, in Code\n");
		return -1;
	}
	fprintf(stdout, "address value: %s\n", addr2->GetText());
	fprintf(stdout, "repositories value: %s\n\n", code->FirstChildElement("Repositories")->GetText());

	return 0;
}

创建xml文件的执行结果如下：

<?xml version="1.0" encoding="UTF-8"?>
<!--this is a xml test file-->
<Root>
    <User Name="fengbingchun">
        <Blog>CSDN</Blog>
        <Code>GitHub</Code>
    </User>
    <Blog Name="CSDN">
        <Address>https://blog.csdn.net/fengbingchun</Address>
        <ID>fengbingchun</ID>
    </Blog>
    <Code Name="GitHub">
        <Address>https://github.com//fengbingchun</Address>
        <Repositories>27</Repositories>
    </Code>
</Root>

解析以上xml文件输出结果如下：

GitHub：https://github.com/fengbingchun/Messy_Test