java之多态

题目：

代码：?

• 测试类

• public class testdemo1 {
      public static void main(String[] args) {
          person li = new person("老李", 45);
          person liu = new person("老刘", 50);
          dog Dog = new dog(2, "black");
          cat Cat = new cat(3, "yellow");
          li.keepPet(Dog,"骨头");
          liu.keepPet(Cat ,"鱼");
  
      }
  }
  

• 动物类

• public class animal {
      private  int age;
      private  String color;
  
      public animal() {
      }
  
      public animal(int age, String color) {
          this.age = age;
          this.color = color;
      }
  
      public int getAge() {
          return age;
      }
  
      public void setAge(int age) {
          this.age = age;
      }
  
      public String getColor() {
          return color;
      }
  
      public void setColor(String color) {
          this.color = color;
      }
  
      public void eat(String something) {
          System.out.println( something);
      }
  }

• dog子类

• public class dog extends animal{
      public dog() {
      }
  
      public dog(int age, String color) {
          super(age, color);
      }
  
      @Override
      public void eat(String something){
         System.out.println("dog eat"+something);
     }
     public void catchMouse(){
         System.out.println("看家");
     }
  
  }
  

• cat子类

• public class cat extends animal {
      public cat() {
      }
  
      public cat(int age, String color) {
          super(age, color);
      }
  
      @Override
      public void eat(String something){
          System.out.println("cat eat"+something);
      }
      public void lookHome(){
          System.out.println("逮老鼠");
      }
  }
  

• person类

• public class person {
      private String name;
      private int age;
  
      public person() {
      }
  
      public person(String name, int age) {
          this.name = name;
          this.age = age;
      }
  
      public String getName() {
          return name;
      }
  
      public void setName(String name) {
          this.name = name;
      }
  
      public int getAge() {
          return age;
      }
  
      public void setAge(int age) {
          this.age = age;
      }
  //    public void keepPet(dog Dog,String something){
  //        System.out.println(age+"岁的老王养了一只"+Dog.getColor()+","+ Dog.getAge()+"岁的宠物"
  //        +"，狗吃"+something);
  //    }
  //    public void keepPet(cat Cat,String something){
  //        System.out.println(age+"岁的老李养了一只"+Cat.getColor()+ ","+Cat.getAge()+"岁的宠物"
  //
  //                +"，猫吃"+something);
  //    }
      //利用多态对keepPet方法进行改写
      public void keepPet(animal a,String something){
          if(a instanceof cat){
              System.out.println(age+"岁的老王养了一只"+a.getColor()+","+ a.getAge()+"岁的宠物"
                          +"，猫吃"+something);
          }else if(a instanceof dog) {
              System.out.println(age+"岁的老王养了一只"+a.getColor()+","+ a.getAge()+"岁的宠物"
                          +"，狗吃"+something);
          }
          else {
              System.out.println("没有这种动物");
          }
      }
  }