C++ boost를 이용한 json 데이터 파싱(parsing)

1. 시험환경

    · 윈도우

    · C++

    · boost

 

2. 목적

    · C++ Boost 라이브러리를 이용하여 json 파일을 읽어서 파싱(parsing)하는 예제 코드를 작성한다.

 

3. 적용

    ① json 샘플 데이터

        - 파일명 : Config.json

{
  "encoding":"UTF-8",  
  "config_type":"dev",
 
  "port":8899,
 
  "log":
  { 
    "max_size":1024,
    "write_file":true,
    "print_screen":true    
  },
 
  "database":
  [
    { 
      "desc":"no.1",
      "address":"127.0.0.1",
      "port":4443,
      "instance":"test_instance1",
      "id":"sa",
      "password":"asdf1234$"
    },
    { 
      "desc":"no.2",
      "address":"127.0.0.1",
      "port":5443,
      "instance":"test_instance2",
      "id":"sa",
      "password":"asdf1234$"
    }
  ]
}

 

 

    ② json 형식의 데이터를 파싱하는 코드이다.

#include <iostream>
 
#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/json_parser.hpp>
 
#include <boost/foreach.hpp>
 
 
int main()
{
    try
    {
        using boost::property_tree::ptree;
        using std::string;
 
        ptree props;
        boost::property_tree::read_json("Config.json", props);
 
 
        string encoding = props.get<string>("encoding");
        std::cout << "Encoding=" << encoding << std::endl;
 
        string config_type = props.get<string>("config_type");
        std::cout << "config_type=" << config_type << std::endl;
 
 
        unsigned short port = props.get<unsigned short>("port");
        std::cout << "port=" << port << std::endl;
 
 
        std::cout << "[Log]" << std::endl;
        ptree &log_child = props.get_child("log");
        int size = log_child.get<int>("max_size"); 
        std::cout << "size=" << size << std::endl;
 
 
        bool write_file = log_child.get<bool>("write_file"); 
        std::cout << "write_file=" << std::boolalpha << write_file << std::endl;
 
        std::cout.setf(std::ios::boolalpha);
        bool print_screen = log_child.get<bool>("print_screen"); 
        std::cout << "print_screen=" << print_screen << std::endl;
 
 
 
        std::cout << "[Database]" << std::endl;
        ptree &db_child = props.get_child("database");
 
        // array!
        int idx = 0;
        BOOST_FOREACH(ptree::value_type &vt, db_child)
        {
            string desc = vt.second.get<string>("desc");
            string address = vt.second.get<string>("address");
            unsigned short port = vt.second.get<unsigned short>("port");
            string instance = vt.second.get<string>("instance");
            string id = vt.second.get<string>("id");
            string password = vt.second.get<string>("password");
 
            std::cout << idx++ << " " << desc << " " << address << " " << port << " " << instance << " " << id << " " << password << std::endl;
        }
 
    }
    catch (std::exception& e)
    {
        std::cout << e.what(); 
    }
 
    return 0;
}