Java开发点餐系统中如何实现账单打印功能

public class Order {
  private String dishName;
  private int quantity;
  private double unitPrice;

  // getters and setters
}

public class Bill {
  private double subTotal;
  private double total;

  // getters and setters
}

public class Printer {
  public void printBill(Order[] orders, Bill bill) {
    // 构建打印内容
    StringBuilder content = new StringBuilder();
    content.append("菜品    数量    单价    小计
");
    for (Order order : orders) {
      content.append(order.getDishName())
             .append("    ")
             .append(order.getQuantity())
             .append("    ")
             .append(order.getUnitPrice())
             .append("    ")
             .append(order.getQuantity() * order.getUnitPrice())
             .append("
");
    }
    content.append("总金额：").append(bill.getTotal());

    // 调用打印机进行打印
    PrinterJob printerJob = PrinterJob.getPrinterJob();
    printerJob.setPrintable(new Printable() {
      @Override
      public int print(Graphics graphics, PageFormat pageFormat, int pageIndex) throws PrinterException {
        if (pageIndex > 0) {
          return Printable.NO_SUCH_PAGE;
        }

        Graphics2D g2d = (Graphics2D) graphics;
        g2d.translate(pageFormat.getImageableX(), pageFormat.getImageableY());
        g2d.drawString(content.toString(), 100, 100);

        return Printable.PAGE_EXISTS;
      }
    });
    try {
      printerJob.print();
    } catch (PrinterException e) {
      e.printStackTrace();
    }
  }
}

public class Main {
  public static void main(String[] args) {
    Order[] orders = {new Order("鱼香肉丝", 2, 12.5), new Order("宫保鸡丁", 1, 15.0)};
    Bill bill = new Bill(40.0, 40.0);

    Printer printer = new Printer();
    printer.printBill(orders, bill);
  }
}