Question

我刚刚创建了一个循环的senario，我必须选择从数据库中选择的列，例如这个带有senario的javaMain

package myrestorderproject;

import enitities.Menu;
import enitities.Tables;
import java.awt.List;
import java.util.ArrayList;
import java.util.Scanner;

/**
 *
 * @author DELL
 */
public class MyRestOrderProject {

    private static Scanner input;

    public static void main(String[] args) {
        // TODO code application logic here
        input = new Scanner(System.in);
        System.out.println("*-*-*-*-*-*Welcome to MyRestaurant*-*-*-*-*-*\n");
        System.out.println("Please Choose Table From Tables List");
        Tables t = new Tables();
        t.getAllRows();
        ArrayList<String> listItem = new ArrayList<String>();
        boolean orderNotFinished = true;

        while (orderNotFinished) {

            System.out.print("Enter Table Number: ");
            String tableNumber = input.nextLine();

            boolean insertedTableNumber = db.goTodataBase.checkTableNumber(tableNumber);
            if (insertedTableNumber) {
                System.out.println("You Choose Table Number: " + tableNumber);
                Menu m = new Menu();
                m.getAllRows();
                while (orderNotFinished) {

                    System.out.println("Please Choose Item From Menu List");

                    input = new Scanner(System.in);
                    String itemChosen = input.nextLine();
                    boolean insertedMenuItemId = db.goTodataBase.checkMenuItemInDB(itemChosen);
                    if (insertedMenuItemId) {
                        System.out.println("You Choose Item ID: " + itemChosen);
                        listItem.add(m.getAllRows(itemChosen));
                        System.out.print("Do you need to add more Items ? ");
                        String hasFinished = input.nextLine();
                        orderNotFinished = hasFinished.equals("yes");

                    } else {
                        System.out.println("Item Chosen doen't exist");
                    }

                }
            } else {
                System.out.println("Table number does not exist");
            }
        }

    }

}

我现在需要在选择合适的项目之后打印“请从菜单列表中选择项目”的部分关闭while循环，我还需要选择多个项目，如果我从菜单中选择项目给我从菜单表中选择了详细信息喜欢如果我选择商品ID 1 +商品ID 2 +商品ID 3表示您已选择项目1蔬菜Pakora 20.00 veg起动器项目1蔬菜Pakora 20.00 veg起动器项目1 Chicken Tikka 20.00非蔬菜初学者之后退出while循环

因为每列都有ID，名称，价格，类型和类别和以前在Senario中使用的方法

public static boolean checkMenuItemInDB(String menuId) {
    try {
        setConnection();
        Statement stmt = con.createStatement();
        String strCheck = "select * from menu where "
                + "Menu_Id=" + menuId;
        stmt.executeQuery(strCheck);
        while (stmt.getResultSet().next()) {                
            return true;
        }
    } catch (Exception e) {
    }
    return false;
}

这是菜单类

package enitities;

import javax.swing.JTable;

/**
 *
 * @author DELL
 */
public class Menu {
    private int Menu_Id;
    private String Name;
    private float Price;
    private String Type;
    private String Category;

    public int getMenu_Id() {
        return Menu_Id;
    }

    public void setMenu_Id(int Menu_Id) {
        this.Menu_Id = Menu_Id;
    }

    public String getName() {
        return Name;
    }

    public void setName(String Name) {
        this.Name = Name;
    }

    public float getPrice() {
        return Price;
    }

    public void setPrice(float Price) {
        this.Price = Price;
    }

    public String getType() {
        return Type;
    }

    public void setType(String Type) {
        this.Type = Type;
    }

    public String getCategory() {
        return Category;
    }

    public void setCategory(String Category) {
        this.Category = Category;
    }
        public void getAllRows() {
        db.goTodataBase.printData("menu");
    }

        public String getAllRows(String itemChosen) {
        db.goTodataBase.printData("menu");
        return itemChosen;
    }
}

这是我在getAllRows

中调用的方法

    public static void printData(String tableNameOrSelectStatement) {
        try {
            setConnection();
            Statement stmt = con.createStatement();
            ResultSet rs;
            String strSelectPart = tableNameOrSelectStatement.substring(0, 4).toLowerCase();
            String strSelect;
            if ("select ".equals(strSelectPart)) {
                strSelect = tableNameOrSelectStatement;
            } else {
                strSelect = "select * from " + tableNameOrSelectStatement;
            }
            rs = stmt.executeQuery(strSelect);

            ResultSetMetaData rsmd = rs.getMetaData();
            int c = rsmd.getColumnCount();
            while (rs.next()) {
                for (int i = 1; i <= c; i++) {
                    if (i > 1) {
                        System.out.print(",  ");
                    }
                    String columnValue = rs.getString(i);
//                    System.out.print(columnValue + " " + rsmd.getColumnName(i));
                    System.out.print(columnValue + " ");

                }
                System.out.println("");
            }

        } catch (Exception e) {
            Tools.msgBox(e.getMessage());
        }
    }

Answer 1

关于循环：

程序员提示：您需要尽可能避免while(true) - 循环。

在您的情况下，您可以使用旗帜系统，它将如下所示：

boolean customerHasFinished = false;
while(!customerHasFinished){
    ...
    //Do your stuff
    ...

    System.out.print("Have you finished ? ");
    String hasFinished = input.nextLine();
    customerHasFinished = hasFinished.equals("yes");
}

关于多个项目：

存储多件商品的最佳方法是使用collection。

在您的情况下，您可能需要创建一个表示Item的Java类。拥有名称，成本等字段然后创建Item的集合。

ArrayList：

的示例

List<Item> listItem = new ArrayList<Item>();
boolean orderNotFinished = true;
while (orderNotFinished) {
    System.out.println("Please Choose an Item From Menu List");
    input = new Scanner(System.in);
    String itemChosen = input.nextLine();
    boolean insertedMenuItemId = db.goTodataBase.checkMenuItemInDB(itemChosen);
    if (insertedMenuItemId) {
        System.out.println("You Choose Item ID: " + itemChosen);
        listItem.add(Item.getItemByName(itemChosen)); //Add the chosen item to the list
        System.out.print("You want something else ? ");
        String hasFinished = input.nextLine();
        orderNotFinished = hasFinished.equals("yes");
    }else {
        System.out.println("Item Chosen doen't exist");
    }
}

如何在java

1 个答案: