JAVA八股与代码实践----接口与抽象类的区别和用法

接口和抽象类的区别

抽象类：定义共同的特征（Cat和Dog都具有Animal的行为，所以可以定义一个Animal抽象类，包含动物的共同行为），比如以下代码

// 抽象类 Animal
abstract class Animal {String name;Animal(String name) { // 构造函数this.name = name;}// 抽象方法：子类必须实现abstract void makeSound();// 具体方法：所有子类共享void sleep() {System.out.println(name + " is sleeping.");}
}// 子类：狗
class Dog extends Animal {Dog(String name) {super(name);}@Overridevoid makeSound() {System.out.println(name + " says: Woof!");}
}// 子类：猫
class Cat extends Animal {Cat(String name) {super(name);}@Overridevoid makeSound() {System.out.println(name + " says: Meow!");}
}// 测试类
public class Main {public static void main(String[] args) {Dog dog = new Dog("Buddy");Cat cat = new Cat("Whiskers");dog.makeSound();dog.sleep();cat.makeSound();cat.sleep();}
}

接口：定义某种行为规范，动物的某个行为作为一个接口，在实际业务中，某个功能服务会作为一个接口，代码示例：

// 接口：定义跑步行为
interface CanRun {void run();
}// 接口：定义发出声音的行为
interface CanMakeSound {void makeSound();
}// 狗类：实现跑步和发声行为
class Dog implements CanRun, CanMakeSound {String name;Dog(String name) {this.name = name;}@Overridepublic void run() {System.out.println(name + " is running!");}@Overridepublic void makeSound() {System.out.println(name + " says: Woof!");}
}// 猫类：实现跑步和发声行为
class Cat implements CanRun, CanMakeSound {String name;Cat(String name) {this.name = name;}@Overridepublic void run() {System.out.println(name + " is running!");}@Overridepublic void makeSound() {System.out.println(name + " says: Meow!");}
}// 测试类
public class Main {public static void main(String[] args) {Dog dog = new Dog("Buddy");Cat cat = new Cat("Whiskers");dog.run();dog.makeSound();cat.run();cat.makeSound();}
}