How to create/read/write JSON files in Qt5

Question

Qt5 has a new JSON parser and I want to use it. The problem is that it isn't too clear about what the functions do in layman's terms and how to write code with it. That or I could be reading it wrong.

I want to know the code on creating a JSON file in Qt5 and what "encapsulates" mean.

Answer 1

Example: Read json from file

/* test.json */ {    "appDesc": {       "description": "SomeDescription",       "message": "SomeMessage"    },    "appName": {       "description": "Home",       "message": "Welcome",       "imp":["awesome","best","good"]    } }   void readJson()    {       QString val;       QFile file;       file.setFileName("test.json");       file.open(QIODevice::ReadOnly | QIODevice::Text);       val = file.readAll();       file.close();       qWarning() << val;       QJsonDocument d = QJsonDocument::fromJson(val.toUtf8());       QJsonObject sett2 = d.object();       QJsonValue value = sett2.value(QString("appName"));       qWarning() << value;       QJsonObject item = value.toObject();       qWarning() << tr("QJsonObject of description: ") << item;        /* in case of string value get value and convert into string*/       qWarning() << tr("QJsonObject[appName] of description: ") << item["description"];       QJsonValue subobj = item["description"];       qWarning() << subobj.toString();        /* in case of array get array and convert into string*/       qWarning() << tr("QJsonObject[appName] of value: ") << item["imp"];       QJsonArray test = item["imp"].toArray();       qWarning() << test[1].toString();    } 

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OUTPUT

QJsonValue(object, QJsonObject({"description": "Home","imp": ["awesome","best","good"],"message": "YouTube"}) )  "QJsonObject of description: " QJsonObject({"description": "Home","imp": ["awesome","best","good"],"message": "YouTube"})  "QJsonObject[appName] of description: " QJsonValue(string, "Home")  "Home"  "QJsonObject[appName] of value: " QJsonValue(array, QJsonArray(["awesome","best","good"]) )  "best"  

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Example: Read json from string

Assign json to string as below and use the readJson() function shown before:

val =    '  {        "appDesc": {           "description": "SomeDescription",           "message": "SomeMessage"        },        "appName": {           "description": "Home",           "message": "Welcome",           "imp":["awesome","best","good"]        }     }'; 

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OUTPUT

QJsonValue(object, QJsonObject({"description": "Home","imp": ["awesome","best","good"],"message": "YouTube"}) )  "QJsonObject of description: " QJsonObject({"description": "Home","imp": ["awesome","best","good"],"message": "YouTube"})  "QJsonObject[appName] of description: " QJsonValue(string, "Home")  "Home"  "QJsonObject[appName] of value: " QJsonValue(array, QJsonArray(["awesome","best","good"]) )  "best"