任务（多线程并行）TFDMemTable内存表传参方式调用服务器返回的TDataSet

服务器端：

function TServerMethods1.getTFDDataSet
( const pSql,pSelectKey:string ):TDataSet;
var iSql,iSelectKey:string;
var FDQry1:TFDQuery; FDCon1:TFDConnection;
ACds:TClientDataSet; TempProvider:TDataSetProvider;
// FDMemTable:TFDMemTable; //内存表处理也可
var Msg:TJSONValue; ifBroadcast:Boolean;
var FieldDefsCount:Integer; AtestCount:Integer;
begin
iSql:=pSql; iSelectKey:=pSelectKey;
//用内存表中转返回值回调的赋值时间:
//FDMemTable:=TFDMemTable.Create(nil);

ACds:=TClientDataSet.Create(nil); //TClientDataSet
if FDConGlobal.Connected=false then
FDConGlobal.Connected:=true;

// FDCon1:=TFDConnection.Create(nil); //FDCon此连接用完后不能释放只能断开交给连接管理员Pooling管理
// FDCon1.ConnectionDefName:='MSSQL';

FDQry1:=TFDQuery.Create(FDConGlobal); //FDQuery此连接用完后不能释放只能断开交给连接管理员Pooling管理
FDQry1.Connection:=FDConGlobal;//:交给全局连接池,不要动态生成连接,否则客户端连续请求时,会提示Socket的IP和Address已经被占用啦

try
FDQry1.FetchOptions.Mode:=fmAll;//FDQry1.FetchOptions.RecordCountMode:=cmTotal;//cmVisible
FDQry1.FetchOptions.RecordCountMode:=cmFetched;
FDQry1.FetchOptions.RowsetSize:=999999;
FDQry1.FetchOptions.RecsMax:=-1;
FDQry1.FetchOptions.RecsSkip:=-1;

// FDMemTable.FetchOptions.Mode:=fmAll;//FDMemTable.FetchOptions.RecordCountMode:=cmTotal; //cmVisible
// FDMemTable.FetchOptions.RecordCountMode:=cmFetched;
// FDMemTable.FetchOptions.RowsetSize:=999999;
// FDMemTable.FetchOptions.RecsMax:=-1;
// FDMemTable.FetchOptions.RecsSkip:=-1;
FDQry1.close; FDQry1.DisableControls;
FDQry1.SQL.Text:=iSql; FDQry1.EnableControls; //' select module_name,Report_name,com_id from ctl04000 ';
FDQry1.Active:=true;//FDQry1.Open(iSql);
FDQry1.First;

while FDQry1.State=dsInactive do sleep(0);
if FDQry1.Active=true then FDQry1.First;
ACds.FieldDefs:=FDQry1.FieldDefs;
//Memo1.Lines.Add('TClientDataSet字段数:'+IntToStr(ACds.FieldDefs.Count));
TempProvider:=TDataSetProvider.Create(nil);
TempProvider.DataSet:=FDQry1; //:TClientDataSet的数据提供者
ACds.Data:=TempProvider.Data;

// if FDMemTable.State<>dsInactive then FDMemTable.Close;//FDMemTable.Active:=false;
// FDMemTable.AppendData(FDQry1);
// MainServerForm.Memo_Errors.Lines.Add('记录数:'+IntToStr(FDMemTable.RecordCount));
// for AtestCount := 0 to FDMemTable.FieldDefs.Count-1 do
// MainServerForm.Memo_Errors.Lines.Add('字段数:'+FDMemTable.FieldDefs[AtestCount].Name);
// Result:=FDMemTable;//:回调客户端请求

while ACds.State=dsInactive do sleep(0);
if ACds.Active=true then ACds.First;

MainServerForm.Memo_Errors.Lines.Add('记录数:'+IntToStr(ACds.RecordCount));
for AtestCount := 0 to ACds.FieldDefs.Count-1 do
MainServerForm.Memo_Errors.Lines.Add('字段数:'+ACds.FieldDefs[AtestCount].Name);
Result:=ACds;

finally
//ACds: TClientDataSet和TFDMemTable本质一样,都是内存缓存的,不需要释放，函数调用完毕后会自动释放,
//若释放啦，因为返回需要时间，返回值会出问题
try
//if ( (testTFDDataSet_ifFinished.Trim).Indexof('OK')>=0 ) then
//:上面的跟踪判断会滞后，要等响应完之后，不要用
FDQry1.Active:=false; while FDQry1.State<>dsInactive do sleep(0);
FreeAndNil(FDQry1);

FreeAndNil(TempProvider);//:TClientDataSet的数据提供者
MainServerForm.Memo_Errors.Lines.Add('组件FDQry1释放成功！');
//FDCon1.Close; //:【数据库连接取完数后】可以断开连接，连接不要释放，交给连接池自动管理。
//:跟DSServerClass1.LifeCycle生命周期管理有关！【用完后】才能释放：需要下面搞清楚什么是【用完后】
except
MainServerForm.Memo_Errors.Lines.Add('释放出错啦');
end;
end;
end;

客户端：

1、公用代码单元（传入TFDMemTable内存表参数调用服务端）：

function getFDMemT_SrvMethGetTFDDataSet(
pSql: string; pSelectKey: string;
var paramFDMemTable: TFDMemTable):Boolean;
var AFDMemTable:TFDMemTable;
ATDataSet:TDataSet; FieldDefsCircle:Integer;
begin
AFDMemTable:=TFDMemTable.Create(nil); //：形参，产生和释放很重要
AFDMemTable.FetchOptions.Mode:=fmAll;
AFDMemTable.FetchOptions.RecordCountMode:=cmFetched;
AFDMemTable.FetchOptions.RowsetSize:=9999999;
AFDMemTable.FetchOptions.RecsMax:=-1;
AFDMemTable.FetchOptions.RecsSkip:=-1;
if AFDMemTable.State<>dsInactive then
begin
AFDMemTable.Close;
end;
try
try
//调用服务器上方法：
//ATDataSet:直接赋值,既不要创建也不要释放:
//if not Assigned(ATDataSet) then //多核多处理器环境,单核环境或win32应用不存在此问题！
ATDataSet:=( ClientModule1.ServerMethods1Client.getTFDDataSet(pSql, pSelectKey) );
while ATDataSet.State=dsInactive do sleep(0); //:确认返回了数据
if ATDataSet.Active=true then
begin
ATDataSet.First;

// 以下：形参获取从服务器返回的ATDataSet:TDataSet数据集数据
AFDMemTable.FieldDefs.Clear;
AFDMemTable.FieldDefs:=ATDataSet.FieldDefs;
AFDMemTable.Open;
while not (ATDataSet.Eof) do
begin
AFDMemTable.Append;
for FieldDefsCircle := 0 to AFDMemTable.FieldDefs.Count-1 do
begin
AFDMemTable.FieldByName(AFDMemTable.FieldDefs[FieldDefsCircle].Name).Value:=ATDataSet.FieldByName(AFDMemTable.FieldDefs[FieldDefsCircle].Name).Value;
end;
AFDMemTable.Post;
ATDataSet.Next;
end;
//Memo1.Lines.Add('TFDMemTable记录数:'+IntToStr(AFDMemTable.RecordCount));
AFDMemTable.First;
AFDMemTable.IndexesActive:=true;
AFDMemTable.Active:=true;  //：形参激活数据，以便下面传递给实参
end;
paramFDMemTable.CloneCursor(AFDMemTable);    //：实参克隆形参的数据和游标
//TMonitor.Exit(AFDMemTable);
except
//on E: TDSRestProtocolException do ClientModule1.HandleRestException(ClientModule1.DSRestConnection1, '客户端连接错误', E); else raise ;
raise Exception.Create('客户端连接错误');
end;
finally
if (AFDMemTable.Active=true)
then Result:=true else Result:=false;
AFDMemTable.Active:=false;    //：形参，施放前线关闭
FreeAndNil(AFDMemTable);    //：形参，产生和释放很重要
end;
end;

2、任务方式执行：内存表传参给公共单元获取数据

procedure TfmxMatter.btnListViewMain_SelectClick(Sender: TObject);
var ATask:ITask; AEvent:TEvent;
ADataSet: TDataSet;
begin
FDMemTMain_Temp.FetchOptions.Mode:=fmAll;
FDMemTMain_Temp.FetchOptions.RecordCountMode:=cmFetched;
FDMemTMain_Temp.FetchOptions.RowsetSize:=9999999;
FDMemTMain_Temp.FetchOptions.RecsMax:=-1;
FDMemTMain_Temp.FetchOptions.RecsSkip:=-1;
if FDMemTMain_Temp.State<>dsInactive then
begin
FDMemTMain_Temp.Close;//FDMemTMain_Temp.Active:=false;
end;

btnListViewMain_EditSelected.Enabled:=false; //:按钮执行任务前加锁很重要
Memo1.Lines.Clear;
//多任务处理预留: if arrayTasks[0].Status=TTaskStatus.Running then arrayTasks[0].Wait(INFINITE);
//ifFinishTask:=0;
AEvent:=TEvent.Create; //:创建事件总线对象
//创建并启动(多线程池化的)任务多核多处理器并行(多路CPU或GPU同时工作,或单处理器多核同步) //APool:= TThreadPool.Create; //：任务POSIX不能带池化参数产生
ATask:=TTask.Create(
procedure
var AtestFieldDefsCircle:Integer;
begin
TMonitor.Enter(self,0); //多核多处理器环境,经常用uses system; //:锁定监视器任务执行前进入锁监视状态：很重要
try
try
try // 调用上述公共单元，获取服务器返回的TDataSet数据 :
getFDMemT_SrvMethGetTFDDataSet(
'select com_id,item_id,item_name,item_type, '
+' convert(Datetime,convert(varchar(23),maintenance_datetime,121)) as maintenance_datetime '
+' from ctl03001','物品资料',FDMemTMain_Temp);
//while FDMemTMain_Temp.State=dsInactive do sleep(0);
finally
if FDMemTMain_Temp.Active=true then FDMemTMain_Temp.First;
//Memo1.Lines.Add('TFDMemTable字段数:'+IntToStr(FDMemTMain_Temp.FieldDefs.Count));
FDMemTMain_Temp.Open;

//Memo1.Lines.Add('TFDMemTable记录数:'+IntToStr(FDMemTMain_Temp.RecordCount));
FDMemTMain_Temp.Last; FDMemTMain_Temp.First;//不像其基类TDataSet,TClientDataSet可以任意操纵Cursor,而且是双向的游标。
FDMemTMain_Temp.IndexesActive:=true;

while not (FDMemTMain_Temp.Eof) do
begin
//此段代码只用于调试，POSIX不允许重复操作
//:Doublication not Allowed:
Memo1.Lines.Add(
'索引字段数:'+IntToStr(FDMemTMain_Temp.IndexFieldCount)+','
+'内存表索引记录数:'+IntToStr(FDMemTMain_Temp.IndexDefs.DataSet.RecordCount)+','
+'内存表索引:'+IntToStr(FDMemTMain_Temp.IndexDefs.DataSet.RecNo-1)+','
+'运营商编码:'+FDMemTMain_Temp.FieldByName('com_id').AsString.Trim+','
+'物品编码:'+FDMemTMain_Temp.FieldByName('item_id').AsString.Trim+','
+'物品名称:'+FDMemTMain_Temp.FieldByName('item_name').AsString.Trim+','
+'型号:'+FDMemTMain_Temp.FieldByName('item_type').AsString.Trim+','
);
FDMemTMain_Temp.Next;
end;
end;
//:上面是任务的具体内容!
AEvent.SetEvent;//:事件总线通知:任务结束!
except // 万一异常,代码很重要 :
TMonitor.Exit(self);
btnListViewMain_EditSelected.Enabled:=true;
AEvent.Free;//:出现异常释放:事件总线!
exit; //:出现异常就不要再往下执行了!
raise Exception.Create('出错或取消啦');
end;
finally
TMonitor.Exit(self); //:锁定监视器适当时机解锁：很重要
btnListViewMain_EditSelected.Enabled:=true; //:按钮适当时机解锁很重要
//AEvent.Free;
//:切忌：将事件总线在try内释放AEvent.Free;
end;
//事件总线AEvent.SetEvent后：确认任务是否完成：
//Assert(AEvent.WaitFor(15000)>TWaitResult.wrSignaled);
//:调试时:确认任务结束时长的信息标记,即AEvent.SetEvent，然后：
AEvent.Free; //:确认收到任务结束的信号标记即AEvent.SetEvent后再：释放事件总线对象
end );
//多任务管理://arrayTasks[0]:=ATask;//TTask.WaitForAll(arrayTasks); //if arrayTasks[0].Status=TTaskStatus.Running then arrayTasks[0].Wait(INFINITE);
ATask.Start;

end;