作为示例，我使用此处列出的XML文件：
https://msdn.microsoft.com/en-us/library/ms256129(v=vs.110).aspx
XML文件：
<?xml version="1.0"?>
<purchaseOrder xmlns="http://tempuri.org/po.xsd" orderDate="1999-10-20">
<shipTo country="US">
<name>Alice Smith</name>
<street>123 Maple Street</street>
<city>Mill Valley</city>
<state>CA</state>
<zip>90952</zip>
</shipTo>
<billTo country="US">
<name>Robert Smith</name>
<street>8 Oak Avenue</street>
<city>Old Town</city>
<state>PA</state>
<zip>95819</zip>
</billTo>
<comment>Hurry, my lawn is going wild!</comment>
<items>
<item partNum="872-AA">
<productName>Lawnmower</productName>
<quantity>1</quantity>
<Price>
<USPrice>148.95</USPrice>
<UKPrice>150.02</UKPrice>
</Price>
<comment>Confirm this is electric</comment>
</item>
<item partNum="926-AA">
<productName>Baby Monitor</productName>
<quantity>1</quantity>
<Price>
<USPrice>39.95</USPrice>
<UKPrice>37.67</UKPrice>
</Price>
<USPrice>39.98</USPrice>
<shipDate>1999-05-21</shipDate>
</item>
</items>
</purchaseOrder>
目前我正在使用以下代码但是使用它我只能读取一个仅为purchaseOrder.shipTo国家的子节点。如何阅读直到标记USPrice？ boost xml解析器是否支持4级标记值解析？
const std::string XML_PATH1 = "./test1.xml";
#define ROOTTAG "purchaseOrder"
boost::property_tree::ptree pt;
boost::property_tree::read_xml( XML_PATH1, pt);
BOOST_FOREACH(boost::property_tree::ptree::value_type & v, pt.get_child(ROOTTAG)){
xmlmap[v.first.data()] = v.second.data();
}
我想在xmlmap <string, string>中阅读并存储如下内容。
map key = items.item partNum.USPrice
map value = 39.98 (post converting to string)
更新
我尝试了以下内容，但它给出了编译错误
error: ‘boost::property_tree::ptree’ has no member named ‘second’
boost::property_tree::ptree lt = subtree.second;
代码：
const std::string XML_PATH1 = "./test1.xml";
#define ROOTTAG "purchaseOrder"
boost::property_tree::ptree pt1;
boost::property_tree::read_xml( XML_PATH1, pt1);
BOOST_FOREACH(boost::property_tree::ptree::value_type & node, pt1.get_child(ROOTTAG))
{
std::string tagname = node.first;
tagname += ".";
boost::property_tree::ptree subtree = node.second;
BOOST_FOREACH( boost::property_tree::ptree::value_type & v, subtree.get_child(node.first.data()))
{
boost::property_tree::ptree lt = subtree.second;
tagname += v.first.data();
tagname += ".";
BOOST_FOREACH( boost::property_tree::ptree::value_type & vt, lt.get_child(v.first.data()))
{
std::string name1 = vt.first.data();
tagname += name1;
if(name1 != "<xmlattr>") {
std::string tagvalue = lt.get<std::string>(name1);
tagname += name1;
xmlmap[tagname] = tagvalue;
}
}
}
}
答案 0 :(得分：0)
这似乎是一件无用的事情。
属性树是/已经/“结构化地图”：
auto po = pt.get_child("purchaseOrder");
std::cout << "items.item.Price.USPrice: '" << po.get("items.item.Price.USPrice", "") << "'\n";
如果需要XPath，请使用支持XPath的XML库（What XML parser should I use in C++?）。
如果您想要更轻松的访问，请编写一些翻译或访问功能。但无论你做什么，你都可能 不 希望通过结构信息，正如你的问题所暗示的那样。
以下是我觉得有用的一些示例：
<强> Live On Coliru
#include <boost/property_tree/xml_parser.hpp>
#include <boost/multiprecision/cpp_dec_float.hpp>
#include <iostream>
#include <map>
using Decimal = boost::multiprecision::cpp_dec_float_50;
using Tree = boost::property_tree::ptree;
namespace BackOffice {
struct purchaseOrder {
struct address {
std::string country, name, street, city, state, zip;
} shipTo, billTo;
std::string comment;
struct item {
std::string partNum, productName, comment;
size_t quantity;
struct Price {
Decimal USPrice, UKPrice;
} price;
};
std::vector<item> items;
};
void read_tree(Tree const& tree, purchaseOrder::address& into);
void read_tree(Tree const& tree, purchaseOrder::item::Price& into);
void read_tree(Tree const& tree, purchaseOrder::item& into);
void read_tree(Tree const& tree, purchaseOrder& into);
template <typename T, typename Indirect>
void read_tree(Indirect const& maybeTree, T& into, decltype(&*maybeTree) = nullptr) {
if (maybeTree) read_tree(*maybeTree, into); else into = {};
}
template <typename T, typename Indirect>
void read_tree(Indirect const& maybeTree, std::string sub, T& into, decltype(&*maybeTree) = nullptr) {
if (maybeTree) read_tree(*maybeTree, sub, into); else into = {};
}
template <typename T>
void read_tree(Tree const& tree, std::string sub, std::vector<T>& into) {
for (auto& child : tree) {
if (child.first == sub) {
into.emplace_back();
read_tree(child.second, into.back());
}
}
}
void read_tree(Tree const& tree, purchaseOrder::address& into) {
into.country = tree.get("<xmlattr>.country", "(unknown");
into.name = tree.get("name", "(unknown");
into.street = tree.get("street", "(unknown");
into.city = tree.get("city", "(unknown");
into.state = tree.get("state", "(unknown");
into.zip = tree.get("zip", "(unknown");
}
void read_tree(Tree const& tree, purchaseOrder::item::Price& into) {
into.UKPrice = tree.get("UKPrice", Decimal{});
into.USPrice = tree.get("USPrice", Decimal{});
}
void read_tree(Tree const& tree, purchaseOrder::item& into) {
into.partNum = tree.get("<xmlattr>.partNum", "(unknown");
into.productName = tree.get("productName", "(unknown");
into.comment = tree.get("comment", "");
read_tree(tree.get_child_optional("Price"), into.price);
}
void read_tree(Tree const& tree, purchaseOrder& into) {
read_tree(tree.get_child_optional("shipTo"), into.shipTo);
read_tree(tree.get_child_optional("billTo"), into.billTo);
read_tree(tree.get_child_optional("items"), "item", into.items);
into.comment = tree.get("comment", "");
}
}
int main() {
Tree pt;
read_xml( "input.txt", pt);
//auto po = pt.get_child("purchaseOrder");
//std::cout << "items.item.Price.USPrice: '" << po.get("items.item.Price.USPrice", "") << "'\n";
BackOffice::purchaseOrder po;
read_tree(pt.get_child("purchaseOrder"), po);
}