java定义shape

在 Java 中，可以使用抽象类和接口来定义形状，如下所示：

// 抽象类 Shape，定义了形状的基本属性和方法
abstract class Shape {
    protected String color;
    protected boolean filled;

    public Shape() {
        color = "red";
        filled = true;
    }

    public Shape(String color, boolean filled) {
        this.color = color;
        this.filled = filled;
    }

    public String getColor() {
        return color;
    }

    public void setColor(String color) {
        this.color = color;
    }

    public boolean isFilled() {
        return filled;
    }

    public void setFilled(boolean filled) {
        this.filled = filled;
    }

    public abstract double getArea();

    public abstract double getPerimeter();

    @Override
    public String toString() {
        return "Shape{" +
                "color='" + color + '\'' +
                ", filled=" + filled +
                '}';
    }
}

// 接口 Drawable，定义了形状的可绘制方法
interface Drawable {
    void draw();
}

// 具体类 Circle，继承自 Shape，实现了 Drawable 接口
class Circle extends Shape implements Drawable {
    protected double radius;

    public Circle() {
        radius = 1.0;
    }

    public Circle(double radius) {
        this.radius = radius;
    }

    public Circle(double radius, String color, boolean filled) {
        super(color, filled);
        this.radius = radius;
    }

    public double getRadius() {
        return radius;
    }

    public void setRadius(double radius) {
        this.radius = radius;
    }

    @Override
    public double getArea() {
        return Math.PI * radius * radius;
    }

    @Override
    public double getPerimeter() {
        return 2 * Math.PI * radius;
    }

    @Override
    public void draw() {
        System.out.println("Drawing Circle");
    }

    @Override
    public String toString() {
        return "Circle{" +
                "radius=" + radius +
                ", color='" + color + '\'' +
                ", filled=" + filled +
                '}';
    }
}

// 具体类 Rectangle，继承自 Shape，实现了 Drawable 接口
class Rectangle extends Shape implements Drawable {
    protected double width;
    protected double length;

    public Rectangle() {
        width = 1.0;
        length = 1.0;
    }

    public Rectangle(double width, double length) {
        this.width = width;
        this.length = length;
    }

    public Rectangle(double width, double length, String color, boolean filled) {
        super(color, filled);
        this.width = width;
        this.length = length;
    }

    public double getWidth() {
        return width;
    }

    public void setWidth(double width) {
        this.width = width;
    }

    public double getLength() {
        return length;
    }

    public void setLength(double length) {
        this.length = length;
    }

    @Override
    public double getArea() {
        return width * length;
    }

    @Override
    public double getPerimeter() {
        return 2 * (width + length);
    }

    @Override
    public void draw() {
        System.out.println("Drawing Rectangle");
    }

    @Override
    public String toString() {
        return "Rectangle{" +
                "width=" + width +
                ", length=" + length +
                ", color='" + color + '\'' +
                ", filled=" + filled +
                '}';
    }
}

在上述代码中，抽象类 `Shape` 定义了形状的基本属性和方法，如颜色、是否填充、获取面积、获取周长等。接口 `Drawable` 定义了形状的可绘制方法 `draw()`。具体类 `Circle` 和 `Rectangle` 继承自 `Shape`，并实现了 `Drawable` 接口，分别实现了自己的属性和方法。