[大数据]boost解析JSON

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boost解析Json 版本1.77

新增json库包含头文件 #include<boost/json.hpp>

/*
boost::json::object 存放json对象
boost::json::array  存放json数组
boost::json::value	存放json数值

写入Json

添加对象
{
	"name":"zhangSan",
	"age":"12"
}
boost::json::object obj_;
obj_["name"] = "zhangSan";
obg_["age"] = "12";
std::cout << obj_ << std::endl;
-------------------------------------------------------------------分割线--------------------------------------------------------------
{
	"name":[1,2,3,4,5]
}

boost::json::array arr_;
boost::json::object ob_;
arr_.push_back(1);
arr_.push_back(2);
arr_.push_back(3);
arr_.push_back(4);
ob_["name"] = arr_;


*/

写入JSON文件

#include <boost/filesystem/fstream.hpp>
#include <boost/json.hpp>
#include <boost/filesystem.hpp>

int main(void)
{
	boost::filesystem::fstream os_;
    os_.open(boost::filesystem::path("a.json"),std::ios_base::out);
    if(!os_.is_open())
    {
        return 0;
    }
    boost::json::object obj;
    boost::json::array arr;
    obj["name"] = boost::json::value("ZhangSan");
    obj["age"] = boost::json::value("12");
	for(int i = 0; i < 10;i++)
    {
        arr.push_back(i);
    }
    obj["num"] = arr;
    os_ << obj;
    os_.close();
    return 0;
}

读JSON文件

/*
	假设文件格式位
	{
		"name":"zhangsan",
		"age":"12",
		"number":[1,2,3,4,5]
	}
*/
#include <iostream>
#include <boost/json/parser.hpp>
#include <boost/json.hpp>
#include <boost/filesystem/fstream.hpp>
int main(void)
{
    boost::filesystem::fstream in_;
    in_.open(boost::filesystem::path("a.json"));
    if(!in_.is_open())
    {
        
        return 0;
    }
    char buf[256];
    std::string str;
    while(!in_.eof())
    {
   		in.getline(buf,sizeof(buf));
        str.append(std::string(buf));
    }
   auto par = boost::json::parse(str);
   for(auto &x : par.as_object())
   {
       std::cout << x.key() << std::endl;
   	   std::cout << x.value() << std::endl;
   }
   in_.close();
   return 0;
}