如何从arraylist中提取特定对象? [英] How do you pull specific objects from an arraylist?

问题描述

我已经创建了Animal超类，鲨鱼和鲸鱼子类.我将用什么来仅从此数组列表中打印出Shark对象?

I've made an Animal superclass, Shark and Whale subclasses. What would I use to print out just the Shark objects from this arraylist?

驱动程序:

import java.util.ArrayList;

public class Creator {     
  public static void main(String[] args){

    ArrayList<Animal> obj = new ArrayList<Animal>();
    obj.add(new Shark("James"));
    obj.add(new Shark("Mike"));
    obj.add(new Whale("Steve"));
    obj.add(new Whale("Tommy"));

    for (Animal a: obj){
    System.out.println(a.getName());
    }
  }
}

推荐答案

您可以使用instanceof从超类Animal的列表中检查特定的子类

You can use the instanceof to check for specific subclass from the list of superclass Animal

for (Animal a: obj){
   if(a instanceof Shark)
    System.out.println(a.getName());
}

这篇关于如何从arraylist中提取特定对象?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！