QT Parsing and assembly JSON

JSON this child familiar and unfamiliar, today to the students talk about how QT is using JSON, a word: simple

1. What is JSON?

A:json is a <key,value> string

① a JSON object

{"Name": "Xupeidong", "Age": "18"}

② nested JSON objects inside a JSON array

[{"Price": "1", "Name": "1", "id": "1"}, {"Price": "2", "Name": "2", "id": "2"}, {"Price": "3", "Name": "3", "id": "3"}]

2. How to use JSON inside QT

#include <QJsonDocument>   //parsing class for converting JSON to Qbytearrar, or parsing from Qbytearray json#include <QJsonArray>   //Encapsulate JSON array: ["1", "2", "3"] #include <QJsonObject>  //Encapsulate JSON object: {"name": "111", "Pass": 222} #include < Qjsonparseerror>//Error class

①json Object

Assembly:

Qjsonobject Json;json.insert ("name", "111"); Json.insert ("Pass", 222); Qjsondocument Doc;doc.setobject (JSON); Qbytearray byte = Document.tojson (Qjsondocument::compact);

Analytical:

Qjsonparseerror error; Qjsondocument doc = Qjsondocument::fromjson (byte, &error); if (Error.error = = qjsonparseerror::noerror) {      if (Doc.isobject ())      {          Qjsonobject obj = Doc.object ();         if (Obj.contains ("name"))  {Qjsonvalue value = Obj.take ("name");　　　　Qdebug () << value.tostring (); }}}    

②json Array

Assembly:

Format: "[\" 000\ ", \" 111\ "]" Qjsonarray json;json.insert (0, "); Json.insert (1," 111 "); Qjsondocument Doc;doc.setarray (JSON); Qbytearray byte = Doc.tojson (Qjsondocument::compact);

You can also insert a JSON object: Format: "[{\" 0\ ": \" 000\ "},{\" 1\ ": \" 111\ "}]" Qjsonarray json; Qjsonobject Obj;obj.insert ("0", "$"); Json.insert (0, obj); Qjsonobject Obj1;obj1.insert ("1", "111"); Json.insert (1, obj1); Qjsondocument Doc;doc.setarray (JSON); Qbytearray byte = Doc.tojson (Qjsondocument::compact);

Analytical:

Qjsonparseerror error; Qjsondocument doc = Qjsondocument::fromjson (byte, &error); if (Error.error = = qjsonparseerror::noerror) {      if (Doc.isarray ())      {          Qjsonarray array = Doc.array ();         for (int i=0; i<array.size (); i++)        {            Qjsonvalue value = array.at (i);}}    }

QT Parsing and assembly JSON