Java语言中的多态技术深入解析

class Animal { 
void makeSound() { 
System.out.println("The animal makes a sound"); 
} 
} 

class Dog extends Animal { 
@Override 
void makeSound() { 
System.out.println("The dog barks"); 
} 
} 

class Cat extends Animal { 
@Override 
void makeSound() { 
System.out.println("The cat meows"); 
} 
} 

public class PolymorphismDemo { 
public static void main(String[] args) { 
Animal animal1 = new Dog(); 
Animal animal2 = new Cat(); 

animal1.makeSound(); // 输出 "The dog barks" 
animal2.makeSound(); // 输出 "The cat meows" 
} 
}

  interface Shape { 
  void draw(); 
  } 
  
  class Circle implements Shape { 
  @Override 
  public void draw() { 
  System.out.println("Drawing a circle"); 
  } 
  } 
  
  class Rectangle implements Shape { 
  @Override 
  public void draw() { 
  System.out.println("Drawing a rectangle"); 
  } 
  } 
  
  public class InterfacePolymorphismDemo { 
  public static void main(String[] args) { 
  Shape shape1 = new Circle(); 
  Shape shape2 = new Rectangle(); 
  
  shape1.draw(); // 输出 "Drawing a circle" 
  shape2.draw(); // 输出 "Drawing a rectangle" 
  } 
  }

// 定义一个Animal接口 
interface Animal { 
void makeSound(); 
} 

// Cat类实现了Animal接口 
class Cat implements Animal { 
@Override 
public void makeSound() { 
System.out.println("The cat says: Meow!"); 
} 
} 

// Dog类实现了Animal接口 
class Dog implements Animal { 
@Override 
public void makeSound() { 
System.out.println("The dog says: Woof!"); 
} 
} 

// Zoo类，用于管理动物 
class Zoo { 
// 使用List存储Animal对象，体现了多态性 
private List<Animal> animals = new ArrayList<>(); 

// 添加动物到动物园 
public void addAnimal(Animal animal) { 
animals.add(animal); 
} 

// 让所有动物发出叫声 
public void makeAllAnimalsSound() { 
for (Animal animal : animals) { 
animal.makeSound(); // 这里体现了多态，调用的是运行时类型的方法 
} 
} 
} 

// 测试类 
public class ZooDemo { 
public static void main(String[] args) { 
Zoo zoo = new Zoo(); 
zoo.addAnimal(new Cat()); 
zoo.addAnimal(new Dog()); 
zoo.makeAllAnimalsSound(); // 输出 "The cat says: Meow!" 和 "The dog says: Woof!" 
} 
}