java - 停留在如何将项目添加到库存列表java上

Question

我已经用java创建了一个库存控制程序，但卡在用户输入部分。用户需要能够从界面的主菜单中选择“添加商品”，然后输入商品的 ID、描述、价格、数量和重新订购级别，然后选择是否要添加添加另一个项目，或退出回到主菜单。

我已经在一组扫描仪中进行了编码，以读取商品属性的输入，但不确定如何将它们添加到我的库存列表中，并且也不确定如果用户想要，我应该使用哪种类型的循环添加另一个项目或导航回主菜单。

有人知道如何最好地解决这些问题吗？任何建议/解决方案将不胜感激。谢谢

库存代码:

public class StockItem {

String itemID;
String itemDesc;
Double price;
int quantity;
int reOrderLevel;
//declaring my instance variables


public StockItem (String itemID, String itemDesc, Double price, int quantity, int reOrderLevel)
{       
        this.itemID = itemID;
        this.itemDesc = itemDesc;
        this.price = price;
        this.quantity = quantity;
        this.reOrderLevel = reOrderLevel;
}
//declaring a contructor with 5 parameters for my instance variables



public String getitemID() {
    return itemID;
}

public String getitemDesc() {
    return itemDesc;
}

public Double getprice() {
    return price;
}

public int getquantity() {
    return quantity;
}

public int getreOrderLevel() {
    return reOrderLevel;
}

//creating my getters for all instance variables


public void setprice(Double price) {
    this.price = price;
}

public void setquantity(int quantity) {
    this.quantity = quantity;
}

public void setreOrderLevel(int reOrderLevel) {
    this.reOrderLevel = reOrderLevel;
}

//creating my setters for 3 instance variables


public String toString()
{
    return getClass().getName() + "itemID: " + itemID + "itemDesc: " + itemDesc + "price:     "
            + price + "quantity: " + quantity + "reOrderLevel: " + reOrderLevel;
}


//public String format() {}





}

库存 list :

import java.util.*;
public class StockList 
{
public static LinkedList<StockItem> stock
        = new LinkedList<StockItem>();


public StockList() {};


// Adds item to end of stock list
public void addItem(StockItem item) 
{
    StockList.stock.addLast(item);
}


// Removes item identified by productID from stock list
public void deleteItem(String itemID) 
{
    ListIterator itr = stock.listIterator();
while(itr.hasNext())
 {
            StockItem item = (StockItem)itr.next();
    if(item.getitemID().equals(itemID))
    {
                    itr.remove();
        break;
    }
    }
}


// Updates price of existing item
public void updateItemPrice(String itemID, double price) 
{
    ListIterator itr = stock.listIterator();
    while(itr.hasNext())
    {
        StockItem item = (StockItem)itr.next();
        if(item.getitemID().equals(itemID))
        {
            item.setprice(price);
            break;
        }
    }

}


// Updates quantity of existing item
public void updateItemQuantity(String itemID, int quantity) 
{
    ListIterator itr = stock.listIterator();
    while(itr.hasNext())
    {
        StockItem item = (StockItem)itr.next();
        if(item.getitemID().equals(itemID))
        {
            item.setquantity(quantity);
            break;
        }
    }
}


// Updates re-order level of existing item
public void updateReOrderLevel(String itemID, 
int reOrderLevel) 
{
    ListIterator itr = stock.listIterator();
    while(itr.hasNext())
    {
        StockItem item = (StockItem)itr.next();
        if(item.getitemID().equals(itemID))
        {
            item.setreOrderLevel(reOrderLevel);
            break;
        }
    }
}


@Override public String toString()
{
  return "" + stock;

}

// Returns formatted representation of the stock list
//  public String formatStockList()
// {…}


// Returns formatted representation of re-order list
// Items are on this list if quantity < reOrderLevel
//  public String formatReOrderList()
//  {…}

ListIterator listIterator() {
    throw new UnsupportedOperationException("Not yet implemented");
}



}

StockList接口(interface):

import java.util.*;
public class StockListInterface
{
private StockList stock = null;

public StockListInterface(StockList stock){}

// Displays main menu and gets valid option from user
public void doMenu()
{
    System.out.println("StockList Main Menu");
    System.out.println("*******************");
    System.out.println("1. Add an Item");
    System.out.println("2. Delete an Item");
    System.out.println("3. Update Item Price");
    System.out.println("4. Update Item Quantity");
    System.out.println("5. Update ReOrder Level");
    System.out.println("6. Print Stock List");
    System.out.println("7. Print ReOrder List");
    System.out.println("8. Exit");

    System.out.println("Select option [1-8] :>");
}


// Obtain input for stock list operation
// and invoke operation 

private void doAddItem(StockItem item) 
{
    StockList.stock.addLast(item);
}

private void doDeleteItem(String itemID)
{
    ListIterator itr = stock.listIterator();
while(itr.hasNext())
 {
            StockItem item = (StockItem)itr.next();
    if(item.getitemID().equals(itemID))
    {
                    itr.remove();
        break;
    }
    }





private void doUpdateItemPrice(String itemID, double price)
{
    ListIterator itr = stock.listIterator();
    while(itr.hasNext())
    {
        StockItem item = (StockItem)itr.next();
        if(item.getitemID().equals(itemID))
        {
            item.setprice(price);
            break;
        }
    }
}





private void doUpdateItemQuantity(String itemID, int quantity)
{
    ListIterator itr = stock.listIterator();
    while(itr.hasNext())
    {
        StockItem item = (StockItem)itr.next();
        if(item.getitemID().equals(itemID))
        {
            item.setquantity(quantity);
            break;
        }
    }
}

private void doUpdateReOrderLevel(String itemID, int reOrderLevel)
{
    ListIterator itr = stock.listIterator();
    while(itr.hasNext())
    {
        StockItem item = (StockItem)itr.next();
        if(item.getitemID().equals(itemID))
        {
            item.setreOrderLevel(reOrderLevel);
            break;
        }
    }
}

// Display contents of stock list
private void doPrintStockList() {}

// Display contents of re-order list
private void doPrintReorderLIst() {}
}

StockListApp:

import java.util.*;
public class StockListInterface
{
private StockList stock = null;

public StockListInterface(StockList stock){}

// Displays main menu and gets valid option from user
public void doMenu()
{
    System.out.println("StockList Main Menu");
    System.out.println("*******************");
    System.out.println("1. Add an Item");
    System.out.println("2. Delete an Item");
    System.out.println("3. Update Item Price");
    System.out.println("4. Update Item Quantity");
    System.out.println("5. Update ReOrder Level");
    System.out.println("6. Print Stock List");
    System.out.println("7. Print ReOrder List");
    System.out.println("8. Exit");

    System.out.println("Select option [1-8] :>");
}


// Obtain input for stock list operation
// and invoke operation 

private void doAddItem(StockItem item) 
{
    StockList.stock.addLast(item);
}

private void doDeleteItem(String itemID)
{
    ListIterator itr = stock.listIterator();
while(itr.hasNext())
 {
            StockItem item = (StockItem)itr.next();
    if(item.getitemID().equals(itemID))
    {
                    itr.remove();
        break;
    }
    }





private void doUpdateItemPrice(String itemID, double price)
{
    ListIterator itr = stock.listIterator();
    while(itr.hasNext())
    {
        StockItem item = (StockItem)itr.next();
        if(item.getitemID().equals(itemID))
        {
            item.setprice(price);
            break;
        }
    }
}


private void doUpdateItemQuantity(String itemID, int quantity)
{
    ListIterator itr = stock.listIterator();
    while(itr.hasNext())
    {
        StockItem item = (StockItem)itr.next();
        if(item.getitemID().equals(itemID))
        {
            item.setquantity(quantity);
            break;
        }
    }
}

private void doUpdateReOrderLevel(String itemID, int reOrderLevel)
{
    ListIterator itr = stock.listIterator();
    while(itr.hasNext())
    {
        StockItem item = (StockItem)itr.next();
        if(item.getitemID().equals(itemID))
        {
            item.setreOrderLevel(reOrderLevel);
            break;
        }
    }
}

// Display contents of stock list
private void doPrintStockList() {}

// Display contents of re-order list
private void doPrintReorderLIst() {}
}

Answer 1

首先有几点评论:

StockItem 中的实例变量应该是私有(private)的。

StockList 有一个公共(public)构造函数，但使用静态列表 - 这意味着 StockList 的所有实例共享相同的列表 - 除非这是您想要的(我猜它不是)，否则您应该将该列表设为非静态。所以只需将其设为私有(private)成员变量即可。

StockListInterface 也应该是一个实际的接口(interface)(如果这是您的意图)。

public interface StockList {
    public void addItem(StockItem item); 
    public void deleteItemById(String itemID); 
    // Updates price of existing item
    public void updateItemPrice(String itemID, double price);
    /// etc.
}

注意，我建议使用deleteItemById，因为您可以轻松提供一个名为deleteItem的方法，该方法采用StockItem，而addItem采用StockItem作为参数而不是字符串。然后进行一个实现(在我看来，这似乎有点矫枉过正，但无论哪种方式都可以争论)，如果是我，一个简单的 StockList 类就足够了。

public class StockListImpl implements StockList {

   private List<StockItem> stockList = new LinkedList<StockItem>();

   public void addItem(StockItem item) {
         stockList.add(item);
   }

  //etc...

请注意，您应该使用泛型来避免类型转换:

private List<StockItem> = new LinkedList<StockItem>();

这样，您将获得一个返回 StockItems 的迭代器，并且无需进行强制转换。所以你可以像这样实现removeItemById:

public void removeItemById(String itemId) {
   Iterator<StockItem> itr = stockList.listIterator();
   while(itr.hasNext()) {
       StockItem item = itr.next();
   if(item.getitemID().equals(itemId)) {
     itr.remove();
     break;
    }
   }
}

所以回答你的问题。

我猜你可能想使用扫描仪 - 请参阅此答案

How to use readline() method in Java?

我认为您需要一种方法来创建每个子菜单，以及另一种方法来接受用户输入并决定显示哪个菜单。这应该与您的 StockList 类分开。

您可以根据自己的喜好使其复杂化，但由于我猜您是初学者，所以基本示例如下:

例如

class StockListApp {

private static Scanner scanner = new Scanner(System.in);

private static final int ADD_ITEM = 1;
private static final int DELETE_ITEM = 2;

private StockListApp() {}

public static void displayRootMenu() {
     System.out.println("StockList Main Menu");
     System.out.println("*******************");
     System.out.println("1. Add an Item");
     System.out.println("2. Delete an Item");
     System.out.println("3. Update Item Price");
     System.out.println("4. Update Item Quantity");
     System.out.println("5. Update ReOrder Level");
     System.out.println("6. Print Stock List");
     System.out.println("7. Print ReOrder List");
     System.out.println("8. Exit");

     System.out.println("Select option [1-8] :>");
     int choice = scanner.nextInt();
     displaySubMenu(choice);
}

private static void displayAddItemMenu() {
    // display menu and read next char from scanner.
}

private static void displayDeleteMenu() {
    // display menu and read next char from scanner.
}


private static void displaySubMenu(int option) {

    switch (option) {
      case StockListApp.ADD_ITEM: {
          displayAddItemMenu();
          break;
      }
      case StockListApp.DELETE_ITEM: {
          displayDeleteMenu();
          break;
      }
    }

}

}

当用户选择退出时，请记住调用scanner.close()。