ShoppingCart 类型的clear() 方法未定义

发布于 2024-11-07 04:59:20 字数 1332 浏览 0 评论 0原文

我正在通过JSP实现一个购物网站。我有一个名为 ShoppingCart 的 Java 对象和一个名为 Item 的 Java 对象。在 ShoppingCart 中，有一个保存 Item 对象的向量。这个想法是，当我调用 addItem() 方法时，我使用：-

cart.addItem(name, image, price, details);

确保 ShoppingCart 已已经声明：-

ShoppingCart cart = new ShoppingCart("file_path_to_file");

以及 的内容>addItem 是：-

public void addItem(String name, String image, String price, String detail) throws IOException  
{  
     items.add(new Item(name, image, price, detail));  
     this.saveMe();  
}

其中 items 是向量。这绝对工作得很好。然而，我现在创建了一个名为clear的新方法：-

public void clear() throws IOException  
{  
    items.clear();  
    this.saveMe();  
}

saveMe方法只是保存到对象文件：-

private void saveMe() throws IOException  
{  
     FileOutputStream fos = new FileOutputStream(this.filename);  
     ObjectOutputStream oos = new ObjectOutputStream(fos)  
     oos.writeObject(this.items);  
     oos.close();  
}

当我使用以下方法调用clear方法时：-

cart.clear();

我收到错误消息：-

jsp文件/project/cart.jsp中第108行发生错误 ShoppingCart 类型的clear() 方法未定义

任何人都可以帮助我尝试解决此问题吗？

原文

I am implementing a shopping website through JSP. I have a Java object called ShoppingCart and one called Item. In ShoppingCart there is a vector which holds Item objects. The idea is when I make a call to the addItem() method, I use:-

cart.addItem(name, image, price, details);

ensuring that the ShoppingCart has already been declared:-

ShoppingCart cart = new ShoppingCart("file_path_to_file");

and the the content of addItem is:-

public void addItem(String name, String image, String price, String detail) throws IOException  
{  
     items.add(new Item(name, image, price, detail));  
     this.saveMe();  
}

where items is the vector. This works absolutely fine. I have, however, now created a new method called clear:-

public void clear() throws IOException  
{  
    items.clear();  
    this.saveMe();  
}

The saveMe method simply saves to an Object file:-

private void saveMe() throws IOException  
{  
     FileOutputStream fos = new FileOutputStream(this.filename);  
     ObjectOutputStream oos = new ObjectOutputStream(fos)  
     oos.writeObject(this.items);  
     oos.close();  
}

When I call the clear method using:-