使用抽象clone()方法克隆超类

Question

代码中的问题是我们不能直接调用Item类型的抽象方法clone，并且我不想修改Item类。有没有办法，或者我应该改变我的逻辑？

 abstract class Item implements Cloneable {

    private boolean stackable; 
    protected String name; 

    public Item()
    {
        this.name      = new String( "Air" );
        this.stackable = true;
    }
    public Item( String name )
    {
        this.name      = name;
        this.stackable = true;
    }
    public abstract Item clone();
}




class Tool extends Item {

    protected double durability; 

    public Tool()
    {
        super("", false);
        this.durability    = 0;          
    }
    public Tool(Tool src)
    {   
        this.durability    = src.durability;              
    }

    public Item clone() throws CloneNotSupportedException {

         Object obj = super.clone();   //problem is here

        return (Item) obj;
   }
}

Answer 1

不知何故，我消除了你的错误

编辑

abstract class Item implements Cloneable{

    private boolean stackable;
    protected String name;

    public Item()
    {
         this.name      = new String( "Air" );
         this.stackable = true;
    }
    public Item( String name, boolean check ) {
        this.name      = name;
        this.stackable = check;
    }

     @Override
     public abstract Item clone() throws CloneNotSupportedException;
}




class Tool extends Item  {

    protected double durability;

    public Tool()
    {
         super("", false);
         this.durability    = 0;
    }
    public Tool(Tool src)
    {
         this.durability    = src.durability;
    }

    @Override
    public Item clone() throws CloneNotSupportedException {

         Item obj = (Item) this.clone();

         return (Item) obj;
    }
}

Answer 2

使用Cloneable接口实现工具类并覆盖clone()

Answer 3

public class Example {
    public static void main(String[] args) throws CloneNotSupportedException {
        Tool t= new Tool();
        System.out.println(t.hashCode());

        Tool t1=(Tool) t.clone();
        System.out.println(t1.hashCode());
    }

}

abstract class Item{

    private boolean stackable;
    protected String name;

    public Item()
    {
        this.name      = new String( "Air" );
        this.stackable = true;
    }
    public Item( String name )
    {
        this.name      = name;
        this.stackable = true;
    }
}




class Tool extends Item implements Cloneable {

    protected double durability;

    public Tool()
    {
        super();
        this.durability    = 0;
    }
    public Tool(Tool src)
    {
        this.durability    = src.durability;
    }

    public Item clone() throws CloneNotSupportedException {

        Object obj = super.clone();   //problem is here

        return (Item) obj;
    }
}