#include <string> #include <iostream> #include "rapidjson/document.h" class MyClass { private: static std::string mVin_; public: static const std::string& GetVin(); static void InitializeVin(const std::string& jsonString); }; std::string MyClass::mVin_ = ""; const std::string& MyClass::GetVin() { return mVin_; } void MyClass::InitializeVin(const std::string& jsonString) { rapidjson::Document document; document.Parse(jsonString.c_str()); if (!document.HasMember("vin")) { std::cerr << "JSON does not contain 'vin' field." << std::endl; return; } mVin_ = document["vin"].GetString(); } int main() { MyClass::InitializeVin("{\"vin\": \"123\"}"); std::cout << MyClass::GetVin() << std::endl; return 0; }分成.h和.cpp文件写

MyClass.h:

#pragma once

#include <string>

class MyClass {
private:
    static std::string mVin_;

public:
    static const std::string& GetVin();
    static void InitializeVin(const std::string& jsonString);
};

MyClass.cpp:

#include "MyClass.h"
#include <iostream>
#include "rapidjson/document.h"

std::string MyClass::mVin_ = "";

const std::string& MyClass::GetVin() {
    return mVin_;
}

void MyClass::InitializeVin(const std::string& jsonString) {
    rapidjson::Document document;
    document.Parse(jsonString.c_str());
    if (!document.HasMember("vin")) {
        std::cerr << "JSON does not contain 'vin' field." << std::endl;
        return;
    }
    mVin_ = document["vin"].GetString();
}

main.cpp:

#include "MyClass.h"
#include <iostream>

int main() {
    MyClass::InitializeVin("{\"vin\": \"123\"}");
    std::cout << MyClass::GetVin() << std::endl;
    return 0;
}