Question

我有一个包含ArrayList的类。我希望能够通过在testClass中调用getOrderItems方法来打印该数组中的所有项目。我遇到了麻烦，返回了数组元素的方式。

这是班级：

package shopping;

import java.util.ArrayList;

public class ShoppingCart {
    private ArrayList<Item> list;


    public ShoppingCart() {
        this.list = new ArrayList<Item>(5);
    }

    public void addItem(Item item1) {
        this.list.add(item1);
    }

    public int getTotal() {
        int total = 0;

        for(Item it : list) {
            total = total + it.getCost();
        }
        return total;
    }

    public void removeItem(Item item1) {
        this.list.remove(item1);
    }

    public int finalizeOrder() {
        int cartSize = this.list.size();
        return cartSize;
    }

    //print elements from ArrayList<Item>
    public String getOrderItems() {
        System.out.println(this.list);
    return null;
  }

}

这是testClass的块：

//email possible & create
        int emailPossible = card.verifyCard();
        if (emailPossible > 0) {
            System.out.println("Email object has been added");
            System.out.println("Your orders was successful and has been placed.\nHere are the details of your order: \n");
            System.out.println("Items:\n------");
            System.out.println(cart.getOrderItems());
        }else{
            System.out.println("Email object has not been added");
        }
        //end email possible & create

但是，我的输出似乎是打印每个项目的地址而不是项目本身：

Email object has been added
Your orders was successful and has been placed.
Here are the details of your order: 

Items:
------
[shopping.Item@677327b6, shopping.Item@14ae5a5, shopping.Item@7f31245a]
null

Answer 1

您应该覆盖toString()类的Item方法。它允许您以自定义方式打印其对象。

Answer 2

通过覆盖类中对象的超类方法来实现toString，并且您能够将列表打印为字符串而不是参考。

从Java中的ArrayList打印元素

2 个答案: