通过使用该Java变量循环遍历类型的arraylist来创建列表

Question

我有Warehouse类型的数组列表。每个仓库都有库存量。方法getStock()返回库存水平。

我有ArrayList Warehouse。我想获取列表中每个仓库的库存并将其添加到列表中。

我的代码：

import java.util.*;

public class Warehouses {

ArrayList<Warehouse> warehouses = new ArrayList<Warehouse>();

public Warehouses() {



    warehouses.add(new Warehouse("W1", 20, "RM13 8BB"));
    warehouses.add(new Warehouse("W2", 28, "RM13 8BB"));
    warehouses.add(new Warehouse("W3", 17, "RM13 8BB"));
}

public void stockList() {



    ArrayList<Integer> stockList = new ArrayList<Integer>();

    for(Warehouse warehouse : warehouses) {

        Integer stock = warehouse.getStock();

        System.out.println(stock);

    }


}
}


class Warehouse
{
// instance variables - replace the example below with your own
private String warehouseID;
private int warehouseStock;
private String location;

/**
 * Constructor for objects of class Warehouse
 */
public Warehouse(String warehouseID, int warehouseStock, String location)
{
    // initialise instance variables
    warehouseID = warehouseID;
    warehouseStock = warehouseStock;
    location = location;
}

public int getStock(){
    return warehouseStock;
}

public String getLocation() {
    return location;
}
}

当我致电stockList()时，我只得到三个空值。这有什么不对？

由于

Answer 1

将Warehouse的构造函数参数分配给类成员变量，而不是自己重新分配局部变量

public Warehouse(String warehouseID, int warehouseStock, String location) {
    this.warehouseID = warehouseID;
    this.warehouseStock = warehouseStock;
    this.location = location;
}