數組列表不顯示正確的輸出

Question

我的主要類代碼

{ 
    ArrayList<Item> items = new ArrayList<Item>(); 
    Scanner file = new Scanner(kk.class.getResourceAsStream("product.txt")); 
    while (file.hasNextLine()) { 
     String[] sp = file.nextLine().split(","); 
     // extract item number, description, price and type 
     itemNum = Integer.parseInt(sp[0]); 
     des = sp[1]; 
     price = Integer.parseInt(sp[2]); 
     Item objt = new Item(itemNum, des, price); // Creating a new object 
     items.add(objt); // Adding it to the list 
    } 
    System.out.println(items); 
} 

輸出我得到

[dada.Item@4a5d4a62，dada.Item@32be8e12，dada.Item@7c6159c4，dada.Item @ 5b4c92a7，dada.Item@3040c5，

我的物品類別代碼

private int itemNum = 0; 
private String des = ""; 
private int price = 0; 

public Item(int i, String d, int p) { 
    itemNum = i; 
    des = d; 
    price = p; 
} 

Answer 1

要打印的Item參考的地址而不是您的Item對象內的字段。通過遍歷它們，您可以在每個Item對象內打印字段。

替換該行

System.out.println(items); 

與

for(Item i : items) 
{ 
    System.out.println(i.getItemNum()+" "+i.getDes()+" "+i.getPrice()); 
} 

更改類，讓你可以訪問你的私人領域

private int itemNum = 0; 
private String des = ""; 
private int price = 0; 

public Item(int i, String d, int p) { 
    itemNum = i; 
    des = d; 
    price = p; 
} 

public void setItemNum(int itemNum) { 
    this.itemNum = itemNum; 
} 
public int getItemNum() { 
    return itemNum; 
} 

public void setDes(String des) { 
    this.des = des; 
} 
public String getDes() { 
    return des; 
} 

public void setPrice(int price) { 
    this.price = price; 
} 
public int getPrice() { 
    return price; 
}