System.JSON.BSON.pas

System.JSON.BSON.pas

这可是DELPHI官方支持BSON的单元。是DELPHI10开始增加的。

TBsonWriter，TBsonReader 分别用于BSON序列和还原。

uses 

System.JSON.BSON,
System.JSON.Writers,
System.JSON.Builders;

procedure BSONWriterSample;
var
  Builder: TJSONObjectBuilder; //To use the built-in JSON builder 
  BytesStream: TBytesStream;  //To create the BSON document as a byte stream
  Writer: TBsonWriter; //A BSON writer
  Bytes: TBytes; //To contain the bytes from the byte stream
begin
  BytesStream := TBytesStream.Create;
  Writer := TBsonWriter.Create(BytesStream);
  Builder := TJSONObjectBuilder.Create(Writer);
  try
    Builder
     .BeginObject
      .BeginArray('colors')
       .BeginObject
        .Add('name','red')
        .Add('hex','#f00')
     .EndAll;

    Bytes := BytesStream.Bytes;
    SetLength(Bytes, BytesStream.Size); //Bytes contains the BSON document.
    Memo1.text := Bytes2String(Bytes); //To see the representation of the BSON document in a TMemo, passing the Bytes var that contains the BSON document.
  finally
    BytesStream.free;
    Writer.free;
    Builder.free;  
  end;
end;

　　

{				
  "colors": [		
    {			
      "name": "red",	
      "hex": "#f00"	
    }			
  ]								
}

　　

function Bytes2String(const ABytes: TBytes): string;
var
  I: Integer;
begin
  Result := '';
  for I := Low(ABytes) to High(ABytes) do
  if I = 0 then
    Result := IntToHex(ABytes[I], 2)
  else
    Result := Result + '-' + IntToHex(ABytes[I], 2);
end;

　　序列JSON对象为BSON：

uses 

System.JSON.BSON,
System.JSON.Writers,
System.JSON.Readers,
System.JSON.Builders;

procedure JSONtoBSON;
var
  SR: TStringReader; //A String Reader
  JsonReader: TJsonTextReader; //A JSON text Reader
  BsonWriter: TBsonWriter; // A BSON writer
  Stream: TBytesStream; //To create the BSON document as a byte stream
  Bytes: TBytes; //To contain the bytes from the byte stream
begin
  SR :=  TStringReader.Create(Memo1.Text); //It gets the JSON object as a string from a TMemo.
  JsonReader := TJsonTextReader.Create(SR);
  Stream := TBytesStream.Create;
  BsonWriter := TBsonWriter.Create(Stream);
  try
    BsonWriter.WriteToken(JsonReader); //It gets the JSON object as an argument and analize the object token by token.
    Stream.Position := 0;
    Bytes := Stream.Bytes;
    SetLength(Bytes, Stream.Size);
    Memo2.Text := Bytes2String(Bytes); //It shows the String representation of the BSON document in a TMemo.
  finally
    SR.free;
    JsonReader.free;
    Stream.free;
    BsonWriter.free;	  
  end;
end;