firedac数据集和字符串之间相互转换

firedac数据集和字符串之间相互转换

/// <author>cxg 2018-12-20</author>

unit DatasetString;

interface

uses

  System.NetEncoding, FireDAC.Stan.Intf, System.ZLib, System.Classes, FireDAC.Comp.Client,

  System.SysUtils;

function DataSetToString(const ADataSet: TFDAdaptedDataSet): string;

function MemTableFromString(const AValue: string): TFDMemTable;

implementation

function DataSetToString(const ADataSet: TFDAdaptedDataSet): string;

var

  LBinary64: string;

  LMemoryStream: TMemoryStream;

  LStringStream: TStringStream;

  LDstStream: TMemoryStream;

  Zipper: TZCompressionStream;

begin

  LDstStream := TMemoryStream.Create;

  try

    LMemoryStream := TMemoryStream.Create;

    try

      ADataSet.SaveToStream(LMemoryStream, TFDStorageFormat.sfBinary);

      LMemoryStream.Seek(0, TSeekOrigin.soBeginning);

      Zipper := TZCompressionStream.Create(clDefault, LDstStream);

      try

        Zipper.CopyFrom(LMemoryStream, LMemoryStream.Size);

      finally

        Zipper.Free;

      end;

    finally

      LMemoryStream.Free;

    end;

    LDstStream.Seek(0, TSeekOrigin.soBeginning);

    LStringStream := TStringStream.Create;

    try

      TNetEncoding.Base64.Encode(LDstStream, LStringStream);

      LBinary64 := LStringStream.DataString;

    finally

      LStringStream.Free;

    end;

  finally

    LDstStream.Free;

  end;

  Result := LBinary64;

end;

function MemTableFromString(const AValue: string): TFDMemTable;

var

  LMemTable: TFDMemTable;

  LStringStream: TStringStream;

  LMemoryStream: TMemoryStream;

  LOrgStream: TMemoryStream;

  Unzipper: TZDecompressionStream;

begin

  LMemTable := TFDMemTable.Create(nil);

  LMemoryStream := TMemoryStream.Create;

  try

    LStringStream := TStringStream.Create(AValue);

    try

      LOrgStream := TMemoryStream.Create;

      try

        TNetEncoding.Base64.Decode(LStringStream, LOrgStream);

        LOrgStream.Seek(0, TSeekOrigin.soBeginning);

        Unzipper := TZDecompressionStream.Create(LOrgStream);

        try

          LMemoryStream.CopyFrom(Unzipper, Unzipper.Size);

        finally

          Unzipper.Free;

        end;

        LMemoryStream.Seek(0, TSeekOrigin.soBeginning);

      finally

        LOrgStream.Free;

      end;

    finally

      LStringStream.Free;

    end;

    LMemTable.LoadFromStream(LMemoryStream, TFDStorageFormat.sfBinary);

  finally

    LMemoryStream.Free;

  end;

  Result := LMemTable;

end;

end.