public abstract class Shape {

    public Shape(String str) {
        // Create object from string representation
    }

    public Shape clone() {
        // Need new way to do this
        return new Shape(this.toString());   
    }

    public String toString() {
        // Correctly overriden toString()
    }
}

解决方法@H_404_6@

你可以尝试使用反射：

public abstract class AClonable implements Cloneable{

private String val;

public AClonable(){

}

public AClonable(String s){
    val=s;
}

public String toString(){
    return val;
}

@Override
public AClonable clone(){
    try {
        System.out.println(getClass().getCanonicalName());
        AClonable b= getClass().getDeclaredConstructor(String.class).newInstance(val);

        return b;
    } catch (InstantiationException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IllegalArgumentException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (SecurityException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (InvocationTargetException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (NoSuchMethodException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return null;
}

}

在clone()方法中调用getClass().因为ACloneble是抽象的,所以会打电话到具体的类.

public class ClonebaleOne extends AClonable{

public ClonebaleOne(){
    super();
}

public ClonebaleOne(String s) {
    super(s);
    // TODO Auto-generated constructor stub
}

}

和

public class ClonebaleTwo extends AClonable{

public ClonebaleTwo(){
    super();
}

public ClonebaleTwo(String s) {
    super(s);
    // TODO Auto-generated constructor stub
}

}

最后

public static void main(String[] args){
    AClonable one = new ClonebaleOne("One");
    AClonable tow= new ClonebaleTwo("Two");
    AClonable clone = one.clone();
    System.out.println(clone.toString());
    clone = tow.clone();
    System.out.println(clone.toString());

}

输出：

ClonebaleOne
  One
  ClonebaleTwo
  Two

但它比解决方案更是一个黑客

[编辑]我的两个克隆比…快)

[编辑]要完成clone()的另一个含义可以是

@Override
public AClonable clone(){
    try {
        ByteArrayOutputStream outByte = new ByteArrayOutputStream();
        ObjectOutputStream outObj = new ObjectOutputStream(outByte);
        ByteArrayInputStream inByte;
        ObjectInputStream inObject;
        outObj.writeObject(this);
        outObj.close();
        byte[] buffer = outByte.toByteArray();
        inByte = new ByteArrayInputStream(buffer);
        inObject = new ObjectInputStream(inByte);
        @SuppressWarnings("unchecked")
        Object deepcopy =  inObject.readObject();
        inObject.close();
        return (AClonable) deepcopy;
    } catch (Exception e) {
        e.printStackTrace();
    }
    return null;
}

当你的抽象类实现Serialazable.在那里,您将您的对象写入光盘,并创建具有光盘值的副本.