Qt中 使用Json 对自定义对象进行序列与反序列化 之一

Posted 2020-07-11

没有使用多态的情况比较简单，完整代码如下：

#include <QCoreApplication>

#include <memory>
#include <vector>
#include <string>
#include <iostream>
#include <algorithm>
#include <QFile>
#include <QJsonDocument>
#include <QJsonObject>
#include <QJsonArray>

class Data
{
public:
    Data(void){}
    Data(const std::wstring &name) : dataName(name){}
    virtual ~Data() {}

    std::wstring getName(void){
        return dataName;
    }

    virtual void write(QJsonObject &json){
        json["Name"] = QString::fromStdWString(dataName.c_str());

    }
    virtual void read(const QJsonObject &json){
        dataName = json["Name"].toString().toStdWString();
    }

    virtual void print(std::wostream &out){
        out << dataName.c_str() << std::endl;
    }

private:
    std::wstring dataName;
};

class DataAnalog : public Data
{
public:
    DataAnalog(void){}
    DataAnalog(const std::wstring &name, const double value):Data(name), dataValue(value) {}
    virtual ~DataAnalog(){}

    virtual void write(QJsonObject &json) override{
        Data::write(json);
        json["Value"] = dataValue;
    }
    virtual void read(const QJsonObject &json) override{
        Data::read(json);
        dataValue = json["Value"].toDouble();
    }

    virtual void print(std::wostream &out){
        out << getName().c_str() << L"=" << dataValue << std::endl;
    }

private:
    double dataValue = 0;
};

class DataDigital : public Data
{
public:
    DataDigital(void) {}
    DataDigital(const std::wstring &name, const bool value):Data(name), dataValue(value){}
    virtual ~DataDigital(){}

    virtual void write(QJsonObject &json) override{
        Data::write(json);
        json["Value"] = dataValue;
    }
    virtual void read(const QJsonObject &json) override{
        Data::read(json);
        dataValue = json["Value"].toBool();
    }

    virtual void print(std::wostream &out) override{
        out << getName().c_str() << L"=" << (dataValue?L"true":L"false") << std::endl;
    }

private:
    bool dataValue = false;
};

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    {//保存
        std::vector<std::shared_ptr<Data>> analogs;
        analogs.emplace_back(new DataAnalog(L"Anlog_1", 1.1));
        analogs.emplace_back(new DataAnalog(L"Anlog_2", 2.2));
        std::vector<std::shared_ptr<Data>> digitals;
        digitals.emplace_back(new DataDigital(L"Digita_1", true));
        digitals.emplace_back(new DataDigital(L"Digita_2", false));

        QFile file(QCoreApplication::applicationDirPath() + "\\data.json");
        if(file.open(QFile::WriteOnly))
        {
            QJsonArray analogArray;
            for(auto data:analogs)
            {
                QJsonObject obj;
                data->write(obj);
                analogArray.append(obj);
            }

            QJsonArray digitalArray;
            for(auto data:digitals)
            {
                QJsonObject obj;
                data->write(obj);
                digitalArray.append(obj);
            }

            QJsonObject json;
            json["Analogs"] = analogArray;
            json["Digitals"] = digitalArray;
            QJsonDocument doc(json);
            file.write(doc.toJson());
        }
    }

    {//加载
        QFile file(QCoreApplication::applicationDirPath() + "\\data.json");
        if(file.open(QFile::ReadOnly))
        {
            QJsonDocument doc = QJsonDocument::fromJson(file.readAll());
            if(!doc.isNull())
            {
                QJsonObject json = doc.object();
                std::vector<std::shared_ptr<Data>> analogs;
                QJsonArray analogArray = json["Analogs"].toArray();
                for(auto i : analogArray)
                {
                    analogs.emplace_back(new DataAnalog());
                    analogs.back()->read(i.toObject());
                }

                std::vector<std::shared_ptr<Data>> digitals;
                QJsonArray digitalArray = json["Digitals"].toArray();
                for(auto i : digitalArray)
                {
                    digitals.emplace_back(new DataDigital());
                    digitals.back()->read((*i).toObject());
                }

                std::for_each(analogs.begin(), analogs.end()
                              , [](std::shared_ptr<Data> data){data->print(std::wcout);});
                std::for_each(digitals.begin(), digitals.end()
                              , [](std::shared_ptr<Data> data){data->print(std::wcout);});
            }
        }
    }


    return a.exec();
}