Delphi语言怎样对自己定义类进行持久化保存及恢复 (性能远比json/xml高)

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Delphi的RTL自身就带有一套非常好的资源持久化保存（IDE设计窗口时，保存为DFM格式及编译到EXE里面的资源文件）及恢复机制（EXE启动时对窗口资源的载入），那么应不是必需再额外用xml/json格式保存程序的參数了。我们大能够将參数集中在一个參数类里面，然后通过这套机制进行保存及恢复。

    因为我们的參数类型可能五花八门。除了传统的整数、小数、字符串、true/false、还有可能是数组、列表、枚举等，则须要override DefineProperties这个函数来自己定义属性的保存及恢复。废话少说，给出代码，此代码演示了怎样自己定义数据的保存及恢复、以及保存整个Form：

	unit Unit1;interfaceusesWinapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes,Vcl.Graphics,Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;typeTArrayOfInteger = array of integer;TSetting = class(TComponent)privatefIntVal: integer;fIntArr: TArrayOfInteger;procedure ReadIntArr(Reader: TReader);procedure WriteIntArr(Writer: TWriter);protectedprocedure DefineProperties(Filer: TFiler); override;publicproperty intArr: TArrayOfInteger read fIntArr write fIntArr;publishedproperty intval: integer read fIntVal write fIntVal;end;TForm1 = class(TForm)btnCloneClass: TButton;mmo1: TMemo;btnCloneForm: TButton;procedure btnCloneClassClick(Sender: TObject);procedure btnCloneFormClick(Sender: TObject);private{ Private declarations }public{ Public declarations }end;varForm1: TForm1;implementation{$R *.dfm}{ TSetting }procedure TSetting.DefineProperties(Filer: TFiler);begininherited;Filer.DefineProperty('intArr', ReadIntArr, WriteIntArr, true);end;procedure TSetting.ReadIntArr(Reader: TReader);varlvIdx: integer;beginfIntArr := nil;Reader.ReadListBegin;SetLength(fIntArr,Reader.ReadInteger);lvIdx:=low(fIntArr);while not Reader.EndOfList dobeginfIntArr[lvIdx] := Reader.ReadInteger;inc(lvIdx);end;Reader.ReadListEnd;end;procedure TSetting.WriteIntArr(Writer: TWriter);vari: integer;beginWriter.WriteListBegin;Writer.WriteInteger(integer(Length(fIntArr)));for i := Low(fIntArr) to High(fIntArr) dobeginWriter.WriteInteger(fIntArr[i]);end;Writer.WriteListEnd;end;function ClassToStr(pvClass: TComponent): ansiString;varinStream, outStream: TMemoryStream;begininStream := TMemoryStream.Create;outStream := TMemoryStream.Create;tryinStream.WriteComponentRes(pvClass.ClassName, pvClass);// inStream.WriteComponent(pvClass);inStream.Position := 0;ObjectResourceToText(inStream, outStream);// ObjectBinaryToText(inStream,outStream);outStream.Position := 0;SetLength(Result, outStream.Size + 1);FillChar(Result[1], outStream.Size + 1, 0);outStream.ReadBuffer(Result[1], outStream.Size);finallyFreeAndNil(inStream);FreeAndNil(outStream);end;end;function StrToClass(pvStr: ansiString; pvCmpToSetProperties: TComponent=nil): TComponent;varinStream, outStream: TMemoryStream;begininStream := TMemoryStream.Create;outStream := TMemoryStream.Create;tryif (pvStr <> '') theninStream.WriteBuffer(pvStr[1], length(pvStr));inStream.Position := 0;ObjectTextToResource(inStream, outStream);// ObjectTextToBinary(inStream,outStream);outStream.Position := 0;Result := outStream.ReadComponentRes(pvCmpToSetProperties);finallyFreeAndNil(inStream);FreeAndNil(outStream);end;end;procedure TForm1.btnCloneClassClick(Sender: TObject);varlvObj, lv1: TSetting;lvStr: String;lvArr: TArrayOfInteger;beginlvObj := TSetting.Create(nil);trylvObj.intval := 12345;SetLength(lvArr, 3);lvArr[0] := 222;lvArr[1] := 333;lvArr[2] := 444;lvObj.intArr := lvArr;lvStr := ClassToStr(lvObj);RegisterClass(TSetting);lvObj.intval := 1;lv1 := TSetting(StrToClass(lvStr, nil));if (lv1.intval > lvObj.intval) thenmmo1.Text := lvStr;finallyFreeAndNil(lvObj);FreeAndNil(lv1);end;// WriteComponentResFile(ExtractFilePath(ParamStr(0))+ 'd.res',self);end;procedure TForm1.btnCloneFormClick(Sender: TObject);var lvNewForm:TForm1;lvRes:string;beginlvRes:=ClassToStr(self);RegisterClass(TForm1);lvNewForm:=TForm1.CreateNew(application);StrToClass(lvRes,lvNewForm);lvNewForm.Left:=self.Left+50;lvNewForm.Top:=self.Top+50;end;end.