RapidXml 读取文件并遍历节点的所有属性

RapidXml 试图成为最快的 XML DOM 解析工具包，同时保证解析结果的可用性、可移植性以及与 W3C 标准的兼容性。RapidXml 使用 C++ 编写，因此在操作同一数据时，其解析速度接近于 strlen() 函数。

整个解析工具包包含在一个头文件中，所以使用时不用编译也不用连接。要想使用 RapidXml 只要包含 rapidxml.hpp 即可，当然如果要用附加功能（如打印函数），你可以包含 rapidxml_print.hpp 文件。

RapidXml 为采用C++语言操作XML提供了机遇，同时结合XMPP协议也开启了诸如Wt、CxServer等基于C++的网络应用在即时通讯领域的更宽广的发展空间。

rapidxml 下载地址：https://sourceforge.net/projects/rapidxml/

测试示例：

读取xml文件，并遍历所有节点的所有属性。xml的文件内容如下：

<?xml version="1.0" encoding="UTF-8"?>
<EllipsoidParams>
<Datum Name="BeiJing54" SemiMajorAxis="6378245.0" Flattening="298.3"/>
<Datum Name="XiAn80" SemiMajorAxis="6378140.0" Flattening="298.257"/>
<Datum Name="CGCS2000" SemiMajorAxis="6378137.0" Flattening="298.257222101"/>
<Datum Name="WGS-84" SemiMajorAxis="6378137.0" Flattening="298.257223563"/>
<Datum Name="WGS-72" SemiMajorAxis="6378135.0" Flattening="298.26"/>
<Datum Name="WGS-66" SemiMajorAxis="6378145.0" Flattening="298.25"/>
<Datum Name="WGS-60" SemiMajorAxis="6378165.0" Flattening="298.3"/>
<Datum Name="Krassovsky" SemiMajorAxis="6378245.0" Flattening="298.3"/>
<Datum Name="International" SemiMajorAxis="6378388.0" Flattening="297.0"/>
<Datum Name="MERIT-83" SemiMajorAxis="6378137.0" Flattening="298.257"/>
<Datum Name="SGS85" SemiMajorAxis="6378136.0" Flattening="298.257"/>
<Datum Name="GRS80" SemiMajorAxis="6378137.0" Flattening="298.257222101"/>
<Datum Name="GRS75" SemiMajorAxis="6378140.0" Flattening="298.257"/>
<Datum Name="Airy 1830" SemiMajorAxis="6377563.396" Flattening="299.3249753150"/>
<Datum Name="Modified Airy" SemiMajorAxis="6377340.189" Flattening="299.32493736548"/>
<Datum Name="Aust_SA" SemiMajorAxis="6378160.0" Flattening="298.25"/>
<Datum Name="Bessel 1841" SemiMajorAxis="6377397.155" Flattening="299.15281285"/>
<Datum Name="Clarke 1880" SemiMajorAxis="6378249.145" Flattening="293.4663"/>
<Datum Name="Clarke 1866" SemiMajorAxis="6378206.4" Flattening="294.9786982139"/>
<Datum Name="GRS67" SemiMajorAxis="6378160.0" Flattening="298.247167427"/>
<Datum Name="APL4.9" SemiMajorAxis="6378137.0" Flattening="298.25"/>
<Datum Name="Andrae" SemiMajorAxis="6377104.43" Flattening="300.0"/>
<Datum Name="Bessel_nam" SemiMajorAxis="6377483.865" Flattening="299.1528128"/>
<Datum Name="CPM" SemiMajorAxis="6375738.7" Flattening="334.29"/>
<Datum Name="Delamber" SemiMajorAxis="6376428.0" Flattening="311.5"/>
<Datum Name="Engelis" SemiMajorAxis="6378136.05" Flattening="298.2566"/>
<Datum Name="Everest30" SemiMajorAxis="6377276.345" Flattening="300.8017"/>
<Datum Name="Everest48" SemiMajorAxis="6377304.063" Flattening="300.8017"/>
<Datum Name="Everest56" SemiMajorAxis="6377301.243" Flattening="300.8017"/>
<Datum Name="Everest69" SemiMajorAxis="6377295.664" Flattening="300.8017"/>
<Datum Name="EverestSS" SemiMajorAxis="6377298.556" Flattening="300.8017"/>
<Datum Name="Fischer60" SemiMajorAxis="6378166.0" Flattening="298.3"/>
<Datum Name="Fischer60m" SemiMajorAxis="6378155.0" Flattening="298.3"/>
<Datum Name="Fischer68" SemiMajorAxis="6378150.0" Flattening="298.3"/>
<Datum Name="Helmert" SemiMajorAxis="6378200.0" Flattening="298.3"/>
<Datum Name="Hough" SemiMajorAxis="6378270.0" Flattening="297.0"/>
<Datum Name="IAU76" SemiMajorAxis="6378140.0" Flattening="298.257"/>
<Datum Name="Kaula" SemiMajorAxis="6378163.0" Flattening="298.24"/>
<Datum Name="Lerch" SemiMajorAxis="6378139.0" Flattening="298.257"/>
<Datum Name="Maupertius" SemiMajorAxis="6397300.0" Flattening="191.0"/>
<Datum Name="New_intl" SemiMajorAxis="6378157.5" Flattening="298.24961539"/>
<Datum Name="NWL9D" SemiMajorAxis="6378145.0" Flattening="298.25"/>
<Datum Name="Plessis" SemiMajorAxis="6376523.0" Flattening="0.0"/>
<Datum Name="Southeast_asia" SemiMajorAxis="6378155.0" Flattening="298.3000002409"/>
<Datum Name="Sphere" SemiMajorAxis="6370997.0" Flattening="298.257"/>
<Datum Name="Walbeck" SemiMajorAxis="6376896.0" Flattening="302.7800001817"/>
</EllipsoidParams>

测试程序代码：
#include <tchar.h>
#include <string>
#include <iostream>
#include "rapidxml/rapidxml.hpp"
#include "rapidxml/rapidxml_utils.hpp"//rapidxml::file
#include "rapidxml/rapidxml_print.hpp"//rapidxml::print
using namespace rapidxml;

std::string ReadFile(const char* fileName)
{
std::string strBuffer;
FILE *fp = fopen(fileName, "rb");
if(NULL == fp)
{
return "";
}

char buf[1024];
while(true)
{
const size_t byteRead = fread(buf, 1, sizeof(buf), fp);
if(0 == byteRead)
{
break;
}
strBuffer.insert(strBuffer.end(), buf, buf+byteRead);
}
fclose(fp);

return strBuffer;
}
//
int ReadFileAndTraversal()
{
//读取文件内容
std::string szFileBuf = ReadFile("./Ellipsoid.xml");

//使用rapidxml::file读取文件更方便
rapidxml::file<> fdoc("Ellipsoid.xml");

//打印读取的内容
std::cout << fdoc.data() << std::endl;

rapidxml::xml_document<> doc;
doc.parse<0>(fdoc.data());
//doc.parse<0>(szFileBuf.c_str());

//打印整个XML内容
std::cout << doc.name() << std::endl;

//在XML文档中寻找第一个节点
const rapidxml::xml_node<> *ellipsoid = doc.first_node("EllipsoidParams");
if(NULL == ellipsoid)
{
return -1;
}

//遍历所有椭球信息
for(rapidxml::xml_node<> *datum = ellipsoid->first_node("Datum");
NULL != datum;
datum = datum->next_sibling())
{
//遍历单个椭球的所有属性
std::string szTmp("");
for(rapidxml::xml_attribute<char> * attr = datum->first_attribute("Name");
attr != NULL;
attr = attr->next_attribute())
{
szTmp.append(attr->name());//name() value()返回的字符串不会去掉首尾的空白字符
szTmp.append(": ");
szTmp.append(attr->value());
szTmp.append(", ");
}
std::cout << szTmp.c_str() << std::endl;
}

return 0;
}

//
int _tmain(int argc, _TCHAR* argv[])
{
//读取文件并打印整个文件
ReadFileAndTraversal();

system("pause");

return 0;
}