打印机池的设计与实现

打印机池的设计与实现

先说一个应用场景——中厨。

服务员先在点菜电脑上点菜，点好的菜单信息要在各出品部的“出品印机”上打印出来，各出品部的师傅再按照菜单来做菜。

不同的菜，要在不同的出品打印机上打印，有的菜要在多个出品打印机上打印。

整个中厨大概有十来个出品部门，有的出品部门有一台出品打印机，有的出口部门有几台。

笔者把这些打印机统称为“打印机池”。

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// 单元功用：打印相关 // 单元设计：cxg // 设计日期：2014-05-12 // 每一台打印机都有自己的任务队列和处理任务队列的线程 // 快餐只有一个出品部门   unit untPrintTask;   interface   uses   System.SysUtils, System.Classes,   Datasnap.DBClient, frxclass,   System.Generics.Collections;   type   TBillContent = record // 小票内容     machineNo: string; // POS机号     skyName: string; // 收款员姓名     saleNo: string; // 小票号     saleTime: TDateTime; // 销售时间     amount: Currency; // 应收     pay: Currency; // 支付     change: Currency; // 找零     prnData: OleVariant; // 小票明细：商品名称、单价、数量、金额。。。。。。     deskNo:string; // 台号     payType: string; // 支付方式   end;   type   TPrinterInfo = record // 打印机信息     prnNo: Integer; // 印机编号     prnName: string; // 印机名称     prnType: string; // 结账、厨打     prnWidth: Integer; // 50mm\76mm\80mm     remark: string; // 备注     prnModel: string; // 打印模版   end;   type   TOneTimePrint = record // 一次打印     printerInfo: TPrinterInfo; // 打印机信息     billContent: TBillContent; // 小票内容   end;   type   TPrintTaskThread = class(TThread)  // 打印任务线程   private     FPrintQueue: TQueue<TOneTimePrint>;   // 打印队列   protected     procedure Execute; override;   public     constructor Create; overload;     destructor Destroy; override;     property PrintQueue: TQueue<TOneTimePrint> read FPrintQueue       write FPrintQueue;   end;   var   g_PrintTasks: TDictionary<string, TPrintTaskThread>;  // <打印机名字, TPrintTask>   implementation   { TPrintTask }   uses untFastReport, UntSysConst;   constructor TPrintTaskThread.Create; begin   Create(False);   FreeOnTerminate := False;   // 创建打印队列   FPrintQueue := TQueue<TOneTimePrint>.Create; end;   destructor TPrintTaskThread.Destroy; begin   // 释放打印队列   FreeAndNil(FPrintQueue);   inherited; end;   procedure TPrintTaskThread.Execute; var   OneTimePrint: TOneTimePrint;   dm: TdmFastReport;   c: TfrxComponent; begin   while not Self.Terminated do   begin     if Assigned(FPrintQueue) and (FPrintQueue.Count > 0) then     begin       // 从任务队列中提取一个任务       OneTimePrint := FPrintQueue.Dequeue;       dm := TdmFastReport.Create(nil);       try         try           // 小票明细数据           dm.cds.Data := OneTimePrint.billContent.prnData;           // 小票模板           dm.report.LoadFromFile(OneTimePrint.printerInfo.prnModel);           // 哪个打印机           dm.report.PrintOptions.Printer := OneTimePrint.printerInfo.prnName;           // 变量赋值             c:=dm.report.FindObject('mmShopName');           if c<>nil then             TfrxMemoView(c).Memo.Text := UserInfo.ShopName;             c := dm.report.FindObject('mmMachineNo');           if c<>nil then             TfrxMemoView(c).Memo.Text := OneTimePrint.billContent.machineNo;             c:=dm.report.FindObject('mmSKY');           if c<>nil then             TfrxMemoView(c).Memo.Text := OneTimePrint.billContent.skyName;             c:= dm.report.FindObject('mmBillNo');           if c<>nil then             TfrxMemoView(c).Memo.Text := OneTimePrint.billContent.saleNo;             c:=dm.report.FindObject('mmSaleTime');           if c<>nil then             TfrxMemoView(c).Memo.Text := FormatDateTime('yyyy-mm-dd hh:nn',OneTimePrint.billContent.saleTime);             c:= dm.report.FindObject('mmDeskNo');           if c<>nil then             TfrxMemoView(c).Memo.Text := OneTimePrint.billContent.deskNo;  // 台号             c:= dm.report.FindObject('mmPayType');           if c<>nil then             TfrxMemoView(c).Memo.Text := OneTimePrint.billContent.payType;             c:= dm.report.FindObject('mmAmount');           if c<> nil then             TfrxMemoView(c).Memo.Text := FormatCurr('0.00', OneTimePrint.billContent.amount);             c:=dm.report.FindObject('mmPay');           if c<>nil then             TfrxMemoView(c).Memo.Text := FormatCurr('0.00', OneTimePrint.billContent.pay);             c:= dm.report.FindObject('mmGiveChange');           if c<> nil then             TfrxMemoView(c).Memo.Text := FormatCurr('0.00', OneTimePrint.billContent.change);             // 开始打印           dm.report.PrepareReport();           dm.report.Print;         except           // 打印失败，重新加入任务队列           Self.FPrintQueue.Enqueue(OneTimePrint);         end;       finally         FreeAndNil(dm);       end;     end;     // 线程休眠     Sleep(1000);   end; end;   end.

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procedure TfrmSettleAccount.PrintBill; var   OneTimePrint: TOneTimePrint;   p: TPrintTaskThread; begin   // 结帐打印机和出品打印机都打印相同的模板   frmPos.cdsPrinter.First;   while not frmPos.cdsPrinter.Eof do   begin     // 打印机信息     OneTimePrint.printerInfo.prnNo := frmPos.cdsPrinter.FieldByName('prnNo')       .AsInteger;     OneTimePrint.printerInfo.prnName := frmPos.cdsPrinter.FieldByName       ('prnName').Text;     OneTimePrint.printerInfo.prnType := frmPos.cdsPrinter.FieldByName       ('prnType').Text;     OneTimePrint.printerInfo.prnWidth := UserInfo.PaperWidth;     OneTimePrint.printerInfo.remark := frmPos.cdsPrinter.FieldByName       ('remark').Text;     // 不同宽度的打印机加载不同的打印模板     case OneTimePrint.printerInfo.prnWidth of       58:         OneTimePrint.printerInfo.prnModel :=           ExtractFilePath(Application.ExeName) + 'report\pos58.fr3';       76:         OneTimePrint.printerInfo.prnModel :=           ExtractFilePath(Application.ExeName) + 'report\pos76.fr3';       80:         OneTimePrint.printerInfo.prnModel :=           ExtractFilePath(Application.ExeName) + 'report\pos80.fr3';     end;     // 小票内容     OneTimePrint.billContent.machineNo := UserInfo.MachineId;     OneTimePrint.billContent.skyName := UserInfo.UserName;     OneTimePrint.billContent.saleNo := UserInfo.saleNo;     OneTimePrint.billContent.saleTime := Now;     OneTimePrint.billContent.amount := self.Total.totalAmount;     OneTimePrint.billContent.pay := self.Total.totalAmount;     OneTimePrint.billContent.Change := StrToCurr(edtChange.Text);     OneTimePrint.billContent.prnData := frmPos.cdsSaleD.Data;     OneTimePrint.billContent.payType := frmPos.cdsSaleM.FieldByName       ('payType').Text;     OneTimePrint.billContent.deskNo := frmPos.edtDeskNo.Text;     // 加入打印队列     if g_PrintTasks.TryGetValue(frmPos.cdsPrinter.FieldByName('prnName').Text, p)     then     begin       p.PrintQueue.Enqueue(OneTimePrint);     end;     frmPos.cdsPrinter.Next;   end; end;