delphi 实体类 JSON 数组 TJsonSerializer Deserialize

delphi 实体类 与JSON转换，序列化

TJson

REST.JSON.pas

System.JSON.Serializers,

 

TJson.JsonToObject
TJson.ObjectToJsonString

JsonEncode

ObjectToJsonObject

 

http://docwiki.embarcadero.com/Libraries/Seattle/en/REST.Json.TJson_Methods

 

 

 从JSONArray中获得JSONObject对象

   JSONObject   jsonObject = (JSONObject)jsonArray.get(i);

 

TJsonReaderTJsonTextWriter

uses System.JSON.Readers,System.JSON.Writers

http://docwiki.embarcadero.com/Libraries/Seattle/en/System.JSON.Readers

http://docwiki.embarcadero.com/Libraries/Seattle/en/System.JSON.Writers

 

http://docwiki.embarcadero.com/Libraries/Seattle/en/System.JSON.Readers.TJsonReader

http://docwiki.embarcadero.com/Libraries/Seattle/en/System.JSON.Writers.TJsonTextWriter

http://docwiki.embarcadero.com/Libraries/Seattle/en/System.JSON.Readers.TJsonReader_Methods

http://docwiki.embarcadero.com/Libraries/Seattle/en/System.JSON.Writers.TJsonTextWriter_Methods

 

来源

http://www.malcolmgroves.com/blog/?p=1084

http://stackoverflow.com/questions/21528552/how-to-bind-contained-objects-with-live-binding

https://community.embarcadero.com/blogs/entry/xe3-visual-livebindings-user-defined-c-objects-32002

 

unit CollectionObjects;

interface

type
  TPerson = class
  private
    FAge: Integer;
    FLastName: string;
    FFirstName: string;
  public
    constructor Create(const FirstName, LastName: String; Age: Integer);
    property FirstName: string read FFirstName write FFirstName;
    property LastName: string read FLastName write FLastName;
    property Age: Integer read FAge write FAge;
  end;

implementation

{ TPerson }

constructor TPerson.Create(const FirstName, LastName: String; Age: Integer);
begin
  FFirstName := FirstName;
  FLastName := LastName;
  FAge := Age;
end;

fMyPeople: TObjectList<TPerson>;

fMyPeople := TObjectList<TPerson>.Create(True);

// The individual TPerson objects
fMyPeople.Add(TPerson.Create('Gomez', 'Addams', 40));
fMyPeople.Add(TPerson.Create('Morticia', 'Addams', 38));
fMyPeople.Add(TPerson.Create('Pugsley', 'Addams', 8));
fMyPeople.Add(TPerson.Create('Wednesday', 'Addams', 12));



// Use TObjectBindSourceAdapter for a single object
ABindSourceAdapter := TListBindSourceAdapter<TPerson>.Create(Self, FMyPeople, True);

function PrettyJSON(AJson: String): String;
begin
Result := StringReplace(AJson, '},', '},' + sLineBreak, [rfReplaceAll]);
Result := StringReplace(Result, '[{', '[' + sLineBreak + '{', [rfReplaceAll]);
end;

procedure TABSMainForm.JsonToObjects;
var
NewPeople: TObjectList<TPerson>;
begin
NewPeople := TJson.JsonToObject<TObjectList<TPerson>>(Memo1.Text);
fMyPeople.Clear;
fMyPeople.AddRange(NewPeople.ToArray);
end;

procedure TABSMainForm.ObjectsToJson;
begin
Memo1.Text := PrettyJSON(TJson.ObjectToJsonString(fMyPeople));
end;

 JsonToObject

ObjectToJsonString

JSON字符串转换为对象

{"ownsObjects":true,"listHelper":[9],"items":[
{"age":40,"lastName":"Addams","firstName":"Gomez"},
{"age":38,"lastName":"Addams","firstName":"Morticia"},
{"age":8,"lastName":"Addams","firstName":"Pugsley"},
{"age":12,"lastName":"Addams","firstName":"Wednesday"},
{"age":55,"lastName":"Fester","firstName":"Uncle"},
{"age":72,"lastName":"Frump","firstName":"Grandmama"},
{"age":50,"lastName":"Lurch","firstName":""},
{"age":99,"lastName":"Thing","firstName":"Thing T."},
{"age":21,"lastName":"Itt","firstName":"Cousin"},
null,null,null,null,null,null,null]}

 TJson::ObjectToJsonString();

数据集转为Json

DataSetConverter4Delphi

https://github.com/ezequieljuliano/DataSetConverter4Delphi

Object>JsonString 类对象序列化为json字符串。

TPerson=class()....

string astr:= TJson.ObjectToJsonString(person);

JsonString反序列化 实例化为类对象

person := TJson.JsonToObject<TPerson>(astr);

Tokyo 10.2新增类，效率更高更快。

TJsonSerializer

Serializer:=TJsonSerializer.Create

String astr=Serializer.Serialize<TPerson>(aperson);

person= nSeriallizer.Deserialize<T>(astring);

感觉TJsonSerializer与.net的开源Newtonsoft.Json类似，功能基本相同了。

TJsonSerializer在c++builder的应用

https://community.embarcadero.com/blogs/entry/10-2-tokyo-tjsonserializer-and-json-converters

First declare with Pascal to use the converter and generics.
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////
unit Unit2;
 
interface
uses
  System.JSON.Converters, System.JSON.Serializers, System.Generics.Collections;
type
  TListString = TList＜String＞;
  TDictionaryStrStr = class(TDictionary＜String, String＞)
    constructor Create; overload;
 
  end;
  TTJsonListConverterString = TJsonListConverter＜String＞;
  TJsonDictionaryConverterStrStr = class(TJsonStringDictionaryConverter＜String＞)
  end;

This is because the use of generics in C++Builder. C++Builder used Win64.
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////
#include ＜System.JSON.Converters.hpp＞
#include ＜System.JSON.Serializers.hpp＞
#include ＜System.Generics.Collections.hpp＞
#include ＜System.JSON.Writers.hpp＞
#include ＜memory＞

 

////
template ＜typename T1, typename T2＞
struct jCollections
{
    UnicodeString _property_name{L""};
    std::unique_ptr＜TStringWriter＞ _string_write{std::make_unique＜TStringWriter＞()};
    std::unique_ptr＜TJsonSerializer＞ _j_serializer{std::make_unique＜TJsonSerializer＞()};
    std::unique_ptr＜TJsonTextWriter＞ _json_writer{std::make_unique＜TJsonTextWriter＞(_string_write.get())};
    jCollections(UnicodeString lname)
    {
        ///Constructor.
        ///Determine the property name.
        _property_name = lname;
    }
    String listtoj(T1 l_list)
    {
        ///Start of object and setting property name.
        _json_writer-＞WriteStartObject();
        _json_writer-＞WritePropertyName(_property_name);
        ///TJsonListConverter__1 or TJsonDictionaryConverterStrStr.
        std::unique_ptr＜T2 ＞ l_json_conv{std::make_unique＜T2 ＞()};
 
        ///Here convert the value of the input list.
        l_json_conv-＞WriteJson(_json_writer.get(), TValue::_op_Implicit(l_list), _j_serializer.get());
        _json_writer-＞WriteEndObject();
        ///returns a string.
        return _string_write-＞ToString();
    }
 
};
void __fastcall TForm1::Button1Click(TObject *Sender)
{
    TList__1＜String＞* l_list= new TList__1＜String＞();
    try
    {
        jCollections＜TList__1＜String＞*, TJsonListConverter__1＜String＞ ＞ _jCollections{L"language_List"};
        l_list-＞Add("Python");
        l_list-＞Add("Delphi");
        l_list-＞Add("C++");
        l_list-＞Add("JAVA");
        l_list-＞Add("ひまわり");
        Memo1-＞Lines-＞Append(_jCollections.listtoj(l_list) );
    }
    __finally
    {
        delete l_list;
    }
 
 
}
//---------------------------------------------------------------------------
void __fastcall TForm1::Button2Click(TObject *Sender)
{
    TDictionaryStrStr* l_dic = new TDictionaryStrStr();
    try
    {
        jCollections＜TDictionaryStrStr*, TJsonDictionaryConverterStrStr ＞ _jCollections{L"2017_MotoGP_standings"};
        l_dic-＞Add("Maverick Vinales", "Movistar Yamaha");
        l_dic-＞Add("Andrea Dovizioso", "Ducati");
        l_dic-＞Add("Valentino Rossi", "Movistar Yamaha");
        l_dic-＞Add("Marc Marquez", "Repsol Honda Team");
        l_dic-＞Add("Dani Pedrosa", "Repsol Honda Team");
        Memo1-＞Lines-＞Append(_jCollections.listtoj(l_dic));
    }
    __finally
    {
        delete l_dic;
    }
 
 
}

Button1 is TList＜String＞ to JSON Convert. Button2 is TDictionary＜String, String＞to JSON.

3.数组json

  TUser = class
  public
    FAge: Integer;
    FLastName: string;
    FFirstName: string;

  end;

 TJsonSerializer的序列化操作，class和 record都支持，使用起来太方便了。

数组2json

procedure TForm3.Button14Click(Sender: TObject);
var
  user: TUser;
  userList: TArray<TUser>;
begin
  user := TUser.Create;
  user.FAge := 1;
  user.FFirstName := 'delphi';
  user.FLastName := 'berlin';

  SetLength(userList, 2);

  userList[0] := user;

  user := TUser.Create;
  user.FFirstName := 'delphi';
  user.FAge := 2;
  user.FLastName := 'tokyo';

  userList[1] := (user);
  self.Memo1.Text := TJsonSerializer.Create.Serialize(userList);

end;

json2数组

procedure TForm3.Button15Click(Sender: TObject);
var
  userList: TArray<TUser>;
  user: TUser;
  i: TArray<Integer>;
begin
  userList := TJsonSerializer.Create.Deserialize < TArray < TUser >> (Memo1.Text);

  Memo2.Clear;
  for user in userList do
  begin
    Memo2.Lines.Add(user.FAge.ToString);
    Memo2.Lines.Add(user.FFirstName);
    Memo2.Lines.Add(user.FLastName);
  end;

end;