继承

• 子类拥有父类非 private 的属性、方法。

• 子类使用父类的public protected属性，方法相当与没写

  package com.example.demo;
  
  import java.util.ArrayList;
  import java.util.List;
  
  public class Test {
      public static void main(String[] args) {
          Animal animal=new Animal();
          animal.update();
          Cat cat=new Cat();
          cat.add(new heart(),animal);
          Animal dog=new Dog(new  heart());
          Animal dog1=new Dog(new  heart());
          dog.toString();
          animal.update();
  
      }
  
  
  }
  class heart{
      protected String name;
  
      public String getName() {
          return name;
      }
  
      public void setName(String name) {
          this.name = name;
      }
  
      @Override
      public String toString() {
          return "heart{" +
                  "name='" + name + '\'' +
                  '}';
      }
  }
  class Animal {
      public List<heart>  hearts= new ArrayList<heart>();
  
  
  
  
  
      @Override
      public String toString() {
          return "Animal{" +
                  "hearts=" + hearts +
                  '}';
      }
      public void update(){
  
          System.out.println(hearts.toString());
          for (heart heart:hearts) System.out.println(heart.getName());
      }
  }
  
  class Cat  {
  
  
      public void add(heart heart,Animal a){
          heart.setName("cay");
          a.hearts.add(heart);
          System.out.println(heart.name);
          System.out.println(a.hearts.toString());
      }
  
  }
  class Dog extends Animal{
      public Dog(heart heart) {
          super();
          heart.setName("dog");
          hearts.add(heart);
          toString();
      }
  
  }

  []
  cay
  [heart{name='cay'}]
  [heart{name='cay'}]
  cay

标签：heart,name,继承,Animal,hearts,new,public
来源： https://www.cnblogs.com/huluxia-fun/p/15416800.html