使用 Boost 序列化和反序列化 JSON

2021-12-24 00:00:00 json c++ boost boost-propertytree

我是 C++ 的新手.使用 boost 序列化和反序列化 std::Map 类型的数据的最简单方法是什么?我找到了一些使用 PropertyTree 的例子，但它们对我来说很模糊.

I'm newbie to C++. What's the easiest way to serialize and deserialize data of type std::Map using boost. I've found some examples with using PropertyTree but they are obscure for me.

推荐答案

注意 property_tree 将键解释为路径，例如放置一对 "a.b"="z" 将创建一个 {"a":{"b":"z"}} JSON，而不是一个 {"a.b":"z"}.否则，使用 property_tree 是微不足道的.这是一个小例子.

Note that property_tree interprets the keys as paths, e.g. putting the pair "a.b"="z" will create an {"a":{"b":"z"}} JSON, not an {"a.b":"z"}. Otherwise, using property_tree is trivial. Here is a little example.

#include <sstream>
#include <map>
#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/json_parser.hpp>

using boost::property_tree::ptree;
using boost::property_tree::read_json;
using boost::property_tree::write_json;

void example() {
  // Write json.
  ptree pt;
  pt.put ("foo", "bar");
  std::ostringstream buf; 
  write_json (buf, pt, false);
  std::string json = buf.str(); // {"foo":"bar"}

  // Read json.
  ptree pt2;
  std::istringstream is (json);
  read_json (is, pt2);
  std::string foo = pt2.get<std::string> ("foo");
}

std::string map2json (const std::map<std::string, std::string>& map) {
  ptree pt; 
  for (auto& entry: map) 
      pt.put (entry.first, entry.second);
  std::ostringstream buf; 
  write_json (buf, pt, false); 
  return buf.str();
}

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