cpp jsoncpp serialize vector class into plain text file and deserialize from plain text file into vector class

//model/book.h
#pragma once
#ifndef __book_h__
#define __book_h__
#include <iostream>

using namespace std;

struct book
{
    uint64_t idx;
    uint64_t id;
    string name;
    string abstract;
    string author;
    string comment;
    string content;
    string summary;
    string topic;
};

#endif

//model/util.h
#pragma once
#ifndef __util_h__
#define __util_h__
#include <chrono>
#include <ctime>
#include <fstream>
#include <iomanip>
#include <iostream>
#include <sstream>
#include <string>
#include <string.h>
#include <unistd.h>
#include <uuid/uuid.h>
#include <vector>
#include <jsoncpp/json/json.h>
#include "model/book.h"

using namespace std;

class util
{
public:
    string get_time_now();
    string get_uuid();
    void fill_book_vector(vector<book> &vec, int len);
    void print_book_vector(vector<book> &vec);
    void book_vector_demo(int len);
    void serialize_book_vector(vector<book>&vec);
    void log_file_msg(string fileName,string msg);
    void serialize_book_demo(int len);
    void deserialize_string_to_vector(string filename);
};

#endif

//model/util.cpp
#include "model/util.h"

std::string util::get_time_now()
{
    chrono::time_point<chrono::high_resolution_clock> now = chrono::high_resolution_clock::now();
    auto ms = chrono::duration_cast<chrono::milliseconds>(now.time_since_epoch()) % 1000;
    time_t rawTime = chrono::high_resolution_clock::to_time_t(now);
    struct tm tmInfo = *localtime(&rawTime);
    stringstream ss;
    ss << std::put_time(&tmInfo, "%Y%m%d%H%M%S") << std::setfill('0') << std::setw(3) << ms.count();
    string dtStr = ss.str();
    ss = stringstream();
    ss.str(std::string());
    return dtStr;
}

std::string util::get_uuid()
{
    uuid_t newUUID;
    uuid_generate(newUUID);
    char *uuidValue = (char *)malloc(40);
    uuid_unparse(newUUID, uuidValue);
    string uuidStr(uuidValue);
    free(uuidValue);
    uuidValue = nullptr;
    return uuidStr;
}

void util::fill_book_vector(vector<book> &vec, int len)
{
    for (int i = 0; i < len; i++)
    {
        book bk;
        bk.idx = static_cast<uint64_t>(i);
        bk.id = static_cast<uint64_t>(i * i * i * i * i);
        bk.abstract.assign(get_uuid());
        bk.author.assign(get_uuid());
        bk.comment.assign(get_uuid());
        bk.content.assign(get_uuid());
        bk.name.assign(get_uuid());
        bk.summary.assign(get_uuid());
        bk.topic.assign(get_uuid());
        vec.push_back(bk);
    }
}

void util::print_book_vector(vector<book> &vec)
{
    vector<book>::iterator itr = vec.begin();
    while (itr != vec.end())
    {
        cout << fixed << itr->idx << "," << itr->id << "," << itr->abstract << "," << itr->author << "," << itr->comment << "," << itr->content << ","
             << itr->name << "," << itr->summary << "," << itr->topic << endl;
        itr++;
    }
}

void util::book_vector_demo(int len)
{
    vector<book> vec;
    fill_book_vector(std::ref(vec), len);
    print_book_vector(std::ref(vec));
    cout << get_time_now() << ",finished in " << __FUNCTION__ << "," << __LINE__ << endl;
}

void util::serialize_book_vector(vector<book> &vec)
{
    Json::Value root;
    vector<book>::iterator itr = vec.begin();
    while (itr != vec.end())
    {
        Json::Value value;
        value["idx"] = itr->idx;
        value["id"] = itr->id;
        value["author"] = itr->author;
        value["abstract"] = itr->abstract;
        value["comment"] = itr->comment;
        value["content"] = itr->content;
        value["name"] = itr->name;
        value["summary"] = itr->summary;
        value["topic"] = itr->topic;
        root.append(value);
        itr++;
    }

    Json::StyledWriter styledWriter;
    string jsonValue = styledWriter.write(root);
    string fileName = get_time_now().append(".txt");
    log_file_msg(fileName, jsonValue);
    cout << get_time_now() << ",finished in " << __FUNCTION__ << "," << __LINE__ << endl;
}

void util::log_file_msg(string fileName, string msg)
{
    fstream wFile(fileName, ios::app);
    if (!wFile.good())
    {
        cout << "Create or open " << fileName << " failed!" << endl;
        return;
    }
    wFile << msg;
    wFile.close();
    cout << get_time_now() << ",finished in " << __FUNCTION__ << "," << __LINE__ << endl;
}

void util::serialize_book_demo(int len)
{
    vector<book> vec;
    fill_book_vector(std::ref(vec), len);
    cout << "size=" << vec.size() << endl;
    serialize_book_vector(std::ref(vec));
    cout << get_time_now() << ",finished in " << __FUNCTION__ << "," << __LINE__ << endl;
}

void util::deserialize_string_to_vector(string filename)
{
    fstream rFile(filename, ios::in);
    if (!rFile.good())
    {
        cout << "Open " << filename << " failed!" << endl;
        return;
    }

    vector<book> vec;
    stringstream ss;
    ss << rFile.rdbuf();
    string jsonvalue = ss.str();
    Json::Value jsonroot;
    Json::Reader jsonreader;
    if (!jsonreader.parse(jsonvalue, jsonroot))
    {
        cout << "Json parsed failed!" << endl;
        return;
    }

    Json::Value::const_iterator citr = jsonroot.begin();
    while (citr != jsonroot.end())
    {
        book bk;
        bk.idx = (*citr)["idx"].asUInt64();
        bk.id = (*citr)["id"].asUInt64();
        bk.abstract = (*citr)["abstract"].asString();
        bk.author = (*citr)["author"].asString();
        bk.comment = (*citr)["comment"].asString();
        bk.content = (*citr)["content"].asString();
        bk.name = (*citr)["name"].asString();
        bk.summary = (*citr)["summary"].asString();
        bk.topic = (*citr)["topic"].asString();
        vec.push_back(bk);
        citr++;
    }

    print_book_vector(std::ref(vec));
    cout << get_time_now() << ",finished in " << __FUNCTION__ << "," << __LINE__ << endl;
}

//main.cpp
#include "model/util.h"

void serialize_book_vector_demo(int len)
{
    util ul;
    ul.serialize_book_demo(len);
}

void deserialize_book_vector_demo(string filename)
{
    util ul;
    ul.deserialize_string_to_vector(filename);
}

int main(int args,char **argv)
{
    deserialize_book_vector_demo(argv[1]);
}

g++ -g -std=c++2a -I. *.cpp ./model/*.cpp -o h1 -luuid -ljsoncpp

//main.cpp
#include "model/util.h"

void serialize_book_vector_demo(int len)
{
    util ul;
    ul.serialize_book_demo(len);
}

void deserialize_book_vector_demo(string filename)
{
    util ul;
    ul.deserialize_string_to_vector(filename);
}

int main(int args,char **argv)
{
    serialize_book_vector_demo(atoi(argv[1]));
    // deserialize_book_vector_demo(argv[1]);
}

g++ -g -std=c++2a -I. *.cpp ./model/*.cpp -o h1 -luuid -ljsoncpp