Boost1.79解析json

boost 解析json

BOOST的版本采用1.79

函数的参数均为使用，内部实现全是写死的demo。

一、写JSON文件

int ReadManager::WriteJson(const std::string&inparam,const std::string &out)
{
    //打开文件
    std::fstream  os;
    os.open(boost::filesystem::current_path().string() + "\\demo.json",std::ios_base::out);
    if(!os.is_open())
    {
        std::cout << "Open Error" << std::endl;
        return -1;
    }
    //设置json内容
    boost::json::object rootObject;	//boost 1.79中 的json对象
    boost::json::array jsonArray;   //boost 1.79中 的json数组 
    jsonArray.reserve(10);	
    for(int i = 0;i < 10;i++)
    {
        jsonArray.push_back(i);     //放入json数组
    }

    boost::json::object childObject;
    childObject["child"] = "childname";	//赋值操作
    childObject["age"] = "12";  		//赋值操作
    rootObject["Persion"] = childObject; //赋值操作
    rootObject["JsonArray"] = jsonArray; //赋值操作
    std::cout << rootObject << std::endl;
    os << rootObject;		//写到文件
    os.close();				//关闭文件
    return 0;
}

二、读取json文件

/*
*  这里读取的文件，为上面函数写的demo.json文件
*/

int ReadManager::ReadJson(const std::string &inparam,const std::string &out) {
    std::string filepath;
    std::string jsonstr;
    if (-1 == LoadStr(filepath, jsonstr))
    {
        return -1;
    }

    //序列化json对象
    boost::json::value jsonvalue = boost::json::parse(jsonstr); //序列化json字符串
    //json序列化后为json对象
    boost::json::object rootObject = jsonvalue.as_object();     //as_object将序列化的内容作为json对象，有其他方法类似as_array具体根据业务选择
    //
    std::cout << rootObject["Persion"] << std::endl;	//直接输出对象中的结果
    std::cout << rootObject["JsonArray"] << std::endl;
    return 0;
}

三、完整代码

头文件

#ifndef __READ__MANAGER__H__
#define __READ__MANAGER__H__

///  boost 1.79
///  boost 1.79
#include <string>
#include <boost/json.hpp>
class ReadManager
{
public:
    //读json文件修改内容
    int ReadJson(const std::string &inparam,const std::string &out);
    //写json文件修改内容
    int WriteJson(const std::string&inparam,const std::string &out);
    //读取文件内容
    int LoadStr(const std::string &filepath,std::string &out);
private:
};
#endif

源文件

#include "read_manager.h"
#include <boost/json.hpp>
#include <boost/json/parse.hpp>
#include <fstream>
#include <iostream>
#include <boost/filesystem.hpp>
#include <boost/json/array.hpp>
#include <boost/json/object.hpp>
int ReadManager::ReadJson(const std::string &inparam,const std::string &out) {
    std::string filepath;
    std::string jsonstr;
    if (-1 == LoadStr(filepath, jsonstr))
    {
        return -1;
    }

    //序列化json对象
    boost::json::value jsonvalue = boost::json::parse(jsonstr);
    //json序列化后为json对象
    boost::json::object rootObject = jsonvalue.as_object();
    //
    std::cout << rootObject["Persion"] << std::endl;
    std::cout << rootObject["JsonArray"] << std::endl;
    return 0;
}

int ReadManager::WriteJson(const std::string&inparam,const std::string &out)
{
    std::fstream  os;
    os.open(boost::filesystem::current_path().string() + "\\demo.json",std::ios_base::out);
    if(!os.is_open())
    {
        std::cout << "Open Error" << std::endl;
        return -1;
    }
    //设置json内容
    boost::json::object rootObject;
    boost::json::array jsonArray;
    jsonArray.reserve(10);
    for(int i = 0;i < 10;i++)
    {
        jsonArray.push_back(i);
    }

    boost::json::object childObject;
    childObject["child"] = "childname";
    childObject["age"] = "12";
    rootObject["Persion"] = childObject;
    rootObject["JsonArray"] = jsonArray;
    std::cout << rootObject << std::endl;
    os << rootObject;
    os.close();
    return 0;
}
int ReadManager::LoadStr(const std::string &filepath,std::string &out)
{
    std::fstream file;
    file.open(boost::filesystem::current_path().string() + "\\demo.json",std::ios_base::in);
    if(!file.is_open())
    {
        std::cout << "Open file error" << std::endl;
        return -1;
    }
    if (file) {

        file.seekg(0, std::ios::end);
        out.resize(file.tellg());
        file.seekg(0, std::ios::beg);
        file.read(&out[0], out.size());
        file.close();
        return 0;
    } else {
        out = "Failed to open the file: " + boost::filesystem::current_path().string() + "\\demo.json";
        return  -1;
    }
}