Java接口和抽象类实现抽象和多态的方法示例

interface InterfaceName {
    ReturnType methodName(Parameters);
}

class ClassName implements InterfaceName {
    // 实现接口中的所有方法
}

interface Drawable {
    void draw();
}
class Circle implements Drawable {
    double radius;
    @Override
    public void draw() {
        System.out.println("Drawing a circle with radius " + radius);
    }
}
class Square implements Drawable {
    double sideLength;
    @Override
    public void draw() {
        System.out.println("Drawing a square with side length " + sideLength);
    }
}
class Main {
    public static void main(String[] args) {
        Circle circle = new Circle();
        circle.radius = 5;
        circle.draw(); // 实现接口的方法
        Square square = new Square();
        square.sideLength = 4;
        square.draw(); // 实现接口的方法
    }
}

interface InterfaceName {
    default ReturnType defaultMethodName(Parameters) {
        // 默认方法的实现
    }
    static ReturnType staticMethodName(Parameters) {
        // 静态方法的实现
    }
}

abstract class AbstractClassName {
    abstract ReturnType methodName(Parameters);
    ReturnType methodName(Parameters) {
        // 具体方法的实现
    }
}

class ClassName extends AbstractClassName {
    // 实现抽象类中的所有抽象方法
}

abstract class Shape {
    abstract double getArea();
    void printArea() {
        System.out.println("The area is " + getArea());
    }
}
class Circle extends Shape {
    double radius;
    @Override
    double getArea() {
        return Math.PI * radius * radius;
    }
}
class Square extends Shape {
    double sideLength;
    @Override
    double getArea() {
        return sideLength * sideLength;
    }
}
class Main {
    public static void main(String[] args) {
        Circle circle = new Circle();
        circle.radius = 5;
        circle.printArea(); // 继承自抽象类的具体方法
        Square square = new Square();
        square.sideLength = 4;
        square.printArea(); // 继承自抽象类的具体方法
    }
}