Datasnap 使用JSON 传递数据的简易方法

在上一篇文章中，使用了 OleVariant;

本文将介绍使用JSON方式来传递。。。

经测试在 windows下、Android 下都没有问题。。苹果则未测试。。。

服务端：

function TServerMethods1.CheckUsernameAndPassword3(U, P: string): TJSONObject;
var
  JO:TJSONObject;
  UserInfo :TLoginUserInfo;
begin
  UserInfo.LoginState := 255 ;   //Defautl: Unknown error
  UserInfo.IsSuperUser := false;
        UserInfo.UserCode := '';
        UserInfo.UserCode := '';
        UserInfo.UserName := '';
        UserInfo.Password := '';
        UserInfo.Deportment := '';
        UserInfo.MachineCode := '';  //设备编号
        UserInfo.AutoPromptMsg :='';
        UserInfo.UserClass :=0 ;
        UserInfo.ProductionWorkShop :='' ;
  with QRY  do begin
    Close;
    SQL.Text :=''; //略过
    Open;
    if not IsEmpty then begin
      if P <> FieldByName('MM').AsString  then begin
        UserInfo.LoginState :=1;
      end else
      if FieldByName('SFJY').AsBoolean then begin
        UserInfo.LoginState :=3;
      end else begin
        UserInfo.LoginState :=0;
        UserInfo.IsSuperUser := FieldByName('CJYH').AsBoolean;
        UserInfo.UserCode := U;
        UserInfo.UserCode := FieldByName('XH').AsString;
        UserInfo.UserName := FieldByName('MC').AsString;
        UserInfo.Password := FieldByName('MM').AsString;
        UserInfo.Deportment := FieldByName('BMBH').AsString;
        UserInfo.MachineCode := FieldByName('SBBH').AsString;  //设备编号
        UserInfo.AutoPromptMsg :='';
        UserInfo.UserClass :=FieldByName('jtsclx').AsInteger ;
        UserInfo.ProductionWorkShop :=FieldByName('SCCJ').AsString ;
      end;
    end else UserInfo.LoginState :=2;
    Close;
    //读是否是验厂
    SQL.Text :=<span style="font-family: Arial, Helvetica, sans-serif;">''; //略过</span>
    Open;
    UserInfo.FactoryEvaluation := FieldByName('FE').AsBoolean;
    Close;
  end;

    JO:=TJSONObject.Create;
    JO.AddPair('LoginState',TJSONNumber.Create(UserInfo.LoginState));
    if UserInfo.IsSuperUser  then
      JO.AddPair('IsSuperUser',TJSONTrue.Create)
    else
      JO.AddPair('IsSuperUser',TJSONFalse.Create);
    JO.AddPair('UserCode',TJSONString.Create(UserInfo.UserCode));
    JO.AddPair('UserName',TJSONString.Create(UserInfo.UserName));
    JO.AddPair('Password',TJSONString.Create(UserInfo.Password));
    JO.AddPair('Deportment',TJSONString.Create(UserInfo.Deportment));
    JO.AddPair('MachineCode',TJSONString.Create(UserInfo.MachineCode));
    JO.AddPair('AutoPromptMsg',TJSONString.Create(UserInfo.AutoPromptMsg));
    JO.AddPair('ProductionWorkShop',TJSONString.Create(UserInfo.ProductionWorkShop) );
    JO.AddPair('UserClass',TJSONNumber.Create(UserInfo.UserClass));
    Result := JO;

客户端：

function Tdm.PubF_CheckLoginUsername3(U, P: string): TLoginUserInfo;
var
  JO:TJSONObject;
begin
  JO := dm.CheckUsernameAndPassword3(U,P);
  Result.LoginState         := StrToIntDef(JO.GetValue('LoginState').Value,255) ;
  Result.IsSuperUser        := JO.GetValue('IsSuperUser').Value='True' ;
  Result.UserCode           := JO.GetValue('UserCode').Value ;
  Result.UserName           := JO.GetValue('UserName').Value ;
  Result.Password           := JO.GetValue('Password').Value ;
  Result.Deportment         := JO.GetValue('Deportment').Value ;
  Result.MachineCode        := JO.GetValue('MachineCode').Value ;
  Result.AutoPromptMsg      := JO.GetValue('AutoPromptMsg').Value ;
  Result.ProductionWorkShop := JO.GetValue('ProductionWorkShop').Value ;
  Result.UserClass          := StrToIntDef(JO.GetValue('UserClass').Value,0);
end;