Delphi语言如何对自定义类进行持久化保存及恢复 (性能远比json/xml高)

        Delphi的RTL自身就带有一套很好的资源持久化保存（IDE设计窗体时，保存为DFM格式及编译到EXE里面的资源文件）及恢复机制（EXE启动时对窗体资源的加载），那么应没必要再额外用xml/json格式保存程序的参数了，我们大可以将参数集中在一个参数类里面，然后通过这套机制进行保存及恢复。

        由于我们的参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，则需要override DefineProperties这个函数来自定义属性的保存及恢复。

        废话少说，给出代码，此代码演示了如何自定义数据的保存及恢复、以及保存整个Form：

unit Unit1;interfaceuses  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes,  Vcl.Graphics,  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;type  TArrayOfInteger = 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;var  Form1: TForm1;implementation{$R *.dfm}{ TSetting }procedure TSetting.DefineProperties(Filer: TFiler);begin  inherited;  Filer.DefineProperty('intArr', ReadIntArr, WriteIntArr, true);end;procedure TSetting.ReadIntArr(Reader: TReader);var  lvIdx: integer;begin  fIntArr := nil;  Reader.ReadListBegin;  SetLength(fIntArr,Reader.ReadInteger);  lvIdx:=low(fIntArr);  while not Reader.EndOfList do  beginfIntArr[lvIdx] := Reader.ReadInteger;inc(lvIdx);  end;  Reader.ReadListEnd;end;procedure TSetting.WriteIntArr(Writer: TWriter);var  i: integer;begin  Writer.WriteListBegin;  Writer.WriteInteger(integer(Length(fIntArr)));  for i := Low(fIntArr) to High(fIntArr) do  beginWriter.WriteInteger(fIntArr[i]);  end;  Writer.WriteListEnd;end;function ClassToStr(pvClass: TComponent): ansiString;var  inStream, outStream: TMemoryStream;begin  inStream := 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;var  inStream, outStream: TMemoryStream;begin  inStream := TMemoryStream.Create;  outStream := TMemoryStream.Create;  tryif (pvStr <> '') then  inStream.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);var  lvObj, lv1: TSetting;  lvStr: String;  lvArr: TArrayOfInteger;begin  lvObj := 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) then  mmo1.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;begin  lvRes:=ClassToStr(self);  RegisterClass(TForm1);  lvNewForm:=TForm1.CreateNew(application);  StrToClass(lvRes,lvNewForm);  lvNewForm.Left:=self.Left+50;  lvNewForm.Top:=self.Top+50;end;end.