C++使用rapidjson进行类的序列化与反序列化

目录

• 序列化&反序列化单个对象
• • 序列化
  • 反序列化
  • 使用示例
• 序列化&反序列化对象列表

C++中可以使用第三方库来实现将类序列化成JSON文件，以及读取JSON文件内容反序列化为类对象。
这里使用rapidJson,github链接：https://github.com/Tencent/rapidjson
使用的话也比较简单，拉下代码，然后将rapidjson-master/include/rapidjson目录拉到自己文件目录下，然后在编译参数上加上-I./rapidjson即可
以下是一个使用RapidJSON库的示例代码：

序列化&反序列化单个对象

序列化

#include <rapidjson/document.h>
#include <rapidjson/writer.h>
#include <rapidjson/stringbuffer.h>

class MyClass {
public:
    int id;
    std::string name;
    double score;

    MyClass(int id, std::string name, double score) : id(id), name(name), score(score) {}
};

void serialize(MyClass& obj, std::string filename) {
    rapidjson::Document doc;
    doc.SetObject();

    rapidjson::Value id;
    id.SetInt(obj.id);
    doc.AddMember("id", id, doc.GetAllocator());

    rapidjson::Value name;
    name.SetString(obj.name.c_str(), obj.name.length(), doc.GetAllocator());
    doc.AddMember("name", name, doc.GetAllocator());

    rapidjson::Value score;
    score.SetDouble(obj.score);
    doc.AddMember("score", score, doc.GetAllocator());

    rapidjson::StringBuffer buffer;
    rapidjson::Writer<rapidjson::StringBuffer> writer(buffer);
    doc.Accept(writer);

    std::ofstream ofs(filename);
    ofs << buffer.GetString();
    ofs.close();
}

反序列化

MyClass deserialize(std::string filename) {
    std::ifstream ifs(filename);
    std::string content((std::istreambuf_iterator<char>(ifs)), std::istreambuf_iterator<char>());
    ifs.close();

    rapidjson::Document doc;
    doc.Parse(content.c_str());

    int id = doc["id"].GetInt();
    std::string name = doc["name"].GetString();
    double score = doc["score"].GetDouble();

    return MyClass(id, name, score);
}

使用示例

int main() {
    MyClass obj(1, "John", 90.5);
    serialize(obj, "myclass.json");

    MyClass new_obj = deserialize("myclass.json");
    std::cout << new_obj.id << " " << new_obj.name << " " << new_obj.score << std::endl;
    return 0;
}

序列化&反序列化对象列表

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include "rapidjson/document.h"
#include "rapidjson/writer.h"
#include "rapidjson/stringbuffer.h"

using namespace rapidjson;

class Person {
public:
    std::string name;
    int age;
    std::string email;

    Person() {}
    Person(const std::string& n, int a, const std::string& e) : name(n), age(a), email(e) {}

    // 序列化为json
    void serialize(Document& doc) const {
        Value obj(kObjectType);
        obj.AddMember("name", Value().SetString(name.c_str(), name.length()), doc.GetAllocator());
        obj.AddMember("age", age, doc.GetAllocator());
        obj.AddMember("email", Value().SetString(email.c_str(), email.length()), doc.GetAllocator());
        doc.PushBack(obj, doc.GetAllocator());
    }

    // 从json反序列化
    void deserialize(const Value& obj) {
        name = obj["name"].GetString();
        age = obj["age"].GetInt();
        email = obj["email"].GetString();
    }
};

// 将类对象的列表序列化为json文件
void serializeToJson(const std::string& filename, const std::vector<Person>& persons) {
    Document doc;
    doc.SetArray();
    for (const auto& person : persons) {
        person.serialize(doc);
    }

    StringBuffer buffer;
    Writer<StringBuffer> writer(buffer);
    doc.Accept(writer);

    std::ofstream ofs(filename);
    ofs << buffer.GetString() << std::endl;
}

// 从json文件中读取内容反序列化为类对象列表
std::vector<Person> deserializeFromJson(const std::string& filename) {
    std::vector<Person> persons;

    std::ifstream ifs(filename);
    if (!ifs.is_open()) {
        std::cerr << "Failed to open file " << filename << std::endl;
        return persons;
    }

    std::string content((std::istreambuf_iterator<char>(ifs)), (std::istreambuf_iterator<char>()));
    Document doc;
    doc.Parse(content.c_str());

    if (!doc.IsArray()) {
        std::cerr << "Invalid json format" << std::endl;
        return persons;
    }

    for (const auto& value : doc.GetArray()) {
        Person person;
        person.deserialize(value);
        persons.push_back(person);
    }

    return persons;
}

int main() {
    std::vector<Person> persons = {
        {"Alice", 30, "alice@example.com"},
        {"Bob", 25, "bob@example.com"},
        {"Charlie", 35, "charlie@example.com"}
    };

    // 序列化为json文件
    serializeToJson("persons.json", persons);

    // 从json文件中反序列化
    std::vector<Person> deserializedPersons = deserializeFromJson("persons.json");

    // 输出反序列化后的结果
    for (const auto& person : deserializedPersons) {
        std::cout << "Name: " << person.name << ", Age: " << person.age << ", Email: " << person.email << std::endl;
    }

    return 0;
}