tinyxml2使用学习

发表于

平时做c/c++开发时经常需要解析xml文件，linux一般就用libxml2做，但是更多时候写的代码需要在linx下跑也要在windows下跑，即使在windows有可能是vc写的还有可能是qt写的。这时解析xml就不那么方便。这里推荐一个tinyxml2开源库，使用了它，解析xml会轻松很多。

tinyxml2的使用比较简单，从官网指定的github地址上下载两个文件（tinyxml2.h、tinyxml2.cpp），然后项目中用到时加入就行了。

这篇文章直接上一个实例，通过这个实例应该可以学会如何使用tinyxml2进行xml的常用操作。

道生一，一生二，二生三，三生万物

废话少说，直接贴代码。

这是提前写好的xml文件：user.xml

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<?xml version="1.0" encoding="utf-8"?>
<users>
	<user name="aaa" age="33"/>
	<user name="bbb" age="22"/>
</users>

这是实例代码文件：test1.cpp

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#include <stdio.h>
#include <iostream>
#include "tinyxml2.h"

using namespace tinyxml2;
using namespace std;

int main()
{
	cout<<"tinyxml2 test1."<<endl;
	cout<<"--------------------------"<<endl;
	cout<<"read from file."<<endl;
	cout<<"--------------------------"<<endl;
	XMLDocument doc;
	if (doc.LoadFile("./user.xml") != 0) {
		cout<<"load xml file failed."<<endl;
		return 1;
	}
	doc.Print();
	cout<<"--------------------------"<<endl;
	cout<<"read from memory."<<endl;
	cout<<"--------------------------"<<endl;
	FILE *fp = fopen("user.xml", "r");
	if (fp == NULL) {
		cout<<"open file failed."<<endl;
		return 1;
	}
	fseek(fp, 0, SEEK_END);
	int len = ftell(fp);
	cout<<"file length is "<<len<<endl;
	char *buf = (char*)malloc(len+1);
	memset(buf, 0, len+1);
	fseek(fp, 0, SEEK_SET);
	fread(buf, len, 1, fp);
	//printf("%s\n", buf);
	XMLDocument doc1;
	doc1.Parse(buf);
	free(buf);
	doc1.Print();
	cout<<"--------------------------"<<endl;
	cout<<"get xml declaration"<<endl;
	cout<<"--------------------------"<<endl;
	XMLNode *decl = doc1.FirstChild();
	XMLDeclaration *declaration = decl->ToDeclaration();
	cout<<declaration->Value()<<endl;
	cout<<"--------------------------"<<endl;
	cout<<"add xml element"<<endl;
	cout<<"--------------------------"<<endl;
	XMLElement *root = doc1.RootElement();
	XMLElement *userNode = doc1.NewElement("user");
	userNode->SetAttribute("name", "ccc");
	userNode->SetAttribute("age", "11");
	root->InsertEndChild(userNode);
	userNode = doc1.NewElement("user");
	userNode->SetAttribute("name", "xiaoming");
	userNode->SetAttribute("age", "22");
	XMLElement *descNode = doc1.NewElement("description");
	XMLText *descText = doc1.NewText("xiaoming is a good boy");
	descNode->InsertEndChild(descText);
	userNode->InsertEndChild(descNode);
	root->InsertEndChild(userNode);
	doc1.Print();
	cout<<"--------------------------"<<endl;
	cout<<"find xml element"<<endl;
	cout<<"--------------------------"<<endl;
	XMLElement *userNode1 = root->FirstChildElement("user");
	while (userNode1 != NULL) {
		const char *name = userNode1->Attribute("name");
		cout<<name<<endl;
		if (strcmp(name, "xiaoming") == 0) {
			XMLElement *descNode1 = userNode1->FirstChildElement("description");
			cout<<descNode1->GetText()<<endl;
		}
		userNode1 = userNode1->NextSiblingElement();
	}
	cout<<"--------------------------"<<endl;
	cout<<"save xml element to file"<<endl;
	cout<<"--------------------------"<<endl;
	doc1.SaveFile("user1.xml");
	cout<<"save ok"<<endl;

	return 0;
}

因为这个例子是一点点写成的，每修改一点就调用g++编译还比较费劲，就写了个makefile

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test1: test1.cpp tinyxml2.cpp
	g++ -o $@ $^

这是执行测试程序后生出来的user1.xml

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<?xml version="1.0" encoding="utf-8"?>
<users>
    <user name="aaa" age="33"/>
    <user name="bbb" age="22"/>
    <user name="ccc" age="11"/>
    <user name="xiaoming" age="22">
        <description>xiaoming is a good boy</description>
    </user>
</users>