JsonDataObjects

{
  "name": "张三", 
  "age": 33,
  "sex": true,
  "weight": 123.456,
  "tel": ["86-1111111", "86-2222222"],
  "addresses":{"address":"A省B市", 
"pc":"100001"},
  "children": [
    {
      "name": "张继",
      "age": "22",
      "sex": true
    },
    {
      "name": "张承",
      "age": "11",
      "sex": false
    }
  ]
}

uses JsonDataObjects;

procedure TForm1.Button1Click(Sender: TObject);
var
    jo: TJsonObject;
    i: Integer;
begin
    jo := TJsonObject.Parse( Memo1.Text) as TJsonObject;

    Memo2.Lines.Add(jo['name']);
    Memo2.Lines.Add(jo['age']);
    Memo2.Lines.Add(jo['sex']);
    Memo2.Lines.Add(jo['weight']);
    Memo2.Lines.Add(jo['tel'].Items[0]);
    Memo2.Lines.Add(jo['tel'].Items[1]);
    Memo2.Lines.Add(jo['addresses'].S['address']);
    Memo2.Lines.Add(jo['addresses'].S['pc']);
    Memo2.Lines.Add('总共数据数:' + inttostr(jo['children'].Count));
    for i := 0 to jo['children'].Count - 1 do
    begin
        Memo2.Lines.Add(jo['children'].Items[i]['name']);
        Memo2.Lines.Add(jo['children'].Items[i]['age']);
        Memo2.Lines.Add(jo['children'].Items[i]['sex']);
    end;
    jo.Free;

----------------------------------------------------------------------------------

Simple example

var
  Obj: TJsonObject;
begin
  Obj := TJsonObject.Parse('{ "foo": "bar", "array": [ 10, 20 ] }') as TJsonObject;
  try
    ShowMessage(Obj['foo']);
    ShowMessage(IntToStr(Obj['array'].Count));
    ShowMessage(IntToStr(Obj['array'].Items[0]));
    ShowMessage(IntToStr(Obj['array'].Items[1]));
  finally
    Obj.Free;
  end;
end;

Filling and serializing JSON objects

var
  Obj, ChildObj: TJsonObject;
begin
  Obj := TJsonObject.Create;
  try
    // easy access
    Obj['foo'] := 'bar';
    // normal (and faster) access
    Obj.S['bar'] := 'foo';
    // automatic array creation, Obj is the owner of 'array'
    Obj.A['array'].Add(10);
    Obj.A['array'].Add(20);
    // automatic object creation, 'array' is the owner of ChildObj
    ChildObj := Obj.A['array'].AddObject;
    ChildObj['value'] := 12.3;
    // automatic array creation, ChildObj is the owner of 'subarray'
    ChildObj.A['subarray'].Add(100);
    ChildObj.A['subarray'].Add(200);

    ShowMessage(Obj.ToJSON({Compact:=}False));
  finally
    Obj.Free;
  end;

{
	"foo": "bar",
	"bar": "foo",
	"array": [
		10,
		20,
		{
			"value": 12.3,
			"subarray": [
				100,
				200
			]
		}
	]
}

Copying JSON objects with Assign

var
  Obj, ClonedObj: TJsonObject;
begin
  Obj := TJsonObject.ParseUtf8('{ "foo": [ "bar", {}, null, true, false, { "key": "value" } ] }') as TJsonObject;
  try
    ClonedObj := TJsonObject.Create;
    try
      // Make a copy of Obj
      ClonedObj.Assign(Obj);
      ShowMessage(ClonedObj.ToJSON(False));
    finally
      ClonedObj.Free;
    end;
  finally
    Obj.Free;
  end;
end;

{
	"foo": [
		"bar",
		{},
		null,
		true,
		false,
		{
			"key": "value"
		}
	]
}