c++怎么将对象序列化为JSON_c++对象JSON序列化与反序列化实现方法

#include <iostream>
#include <string>
#include <nlohmann/json.hpp>

using json = nlohmann::json;

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

    // 序列化：对象 → JSON
    json to_json() const {
        return json{
            {"name", name},
            {"age", age},
            {"email", email}
        };
    }

    // 反序列化：JSON → 对象
    void from_json(const json& j) {
        name = j.value("name", "");
        age = j.value("age", 0);
        email = j.value("email", "");
    }
};

User user{"张三", 25, "zhangsan@example.com"};

// 序列化为JSON字符串
json j = user.to_json();
std::string json_str = j.dump(4); // 格式化输出，缩进4格
std::cout << json_str << std::endl;

{
    "age": 25,
    "email": "zhangsan@example.com",
    "name": "张三"
}

json j2 = json::parse(json_str);
User user2;
user2.from_json(j2);

namespace nlohmann {
template<>
struct adl_serializer<User> {
    static void to_json(json& j, const User& u) {
        j = json{{"name", u.name}, {"age", u.age}, {"email", u.email}};
    }

    static void from_json(const json& j, User& u) {
        u.name = j.at("name").get<std::string>();
        u.age = j.at("age").get<int>();
        u.email = j.at("email").get<std::string>();
    }
};
}

json j = user;                    // 自动调用to_json
User user2 = j.get<User>();       // 自动调用from_json