Delphi中的base64编码

引用System.NetEncoding单元，实现代码片断：

var
  base64:TBase64Encoding;
  GBKEncoding:TEncoding;
begin
  base64:=TBase64Encoding.Create;
  GBKEncoding:=TEncoding.GetEncoding(CP_UTF8);
  Result:=base64.EncodeBytesToString(GBKEncoding.GetBytes(data));
  GBKEncoding.Free;
  base64.Free;
end;