1．编写一个抽象类(Shape)，长方形、三角形和圆形均为其子类，并各有各的属性。其父类中有计算周长和面积的方法。在测试类中，分别建立如干个对象，计算并输出各对象的周长和面积。

首先，我们可以创建一个名为`Shape`的抽象类，作为所有形状的基础类型。这个抽象类将包含一些通用的属性，如`color`，以及两个抽象方法`calculatePerimeter`和`calculateArea`，表示计算周长和面积的行为：

abstract class Shape {
    String color;

    abstract double calculatePerimeter();
    abstract double calculateArea();

    // 构造函数可以设置颜色等实例变量
    public Shape(String color) {
        this.color = color;
    }
}

// 具体的子类，比如Rectangle, Triangle和Circle
class Rectangle extends Shape {
    private double length;
    private double width;

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

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

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

class Triangle extends Shape {
    private double base;
    private double height;

    public Triangle(String color, double base, double height) {
        super(color);
        this.base = base;
        this.height = height;
    }

    @Override
    double calculatePerimeter() {
        // 实现三角形周长计算...
    }

    @Override
    double calculateArea() {
        // 实现三角形面积计算...
    }
}

class Circle extends Shape {
    private double radius;

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

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

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

然后，在测试类`Main`中，你可以创建这些形状的对象，计算它们的周长和面积，然后打印出来：

public class Main {
    public static void main(String[] args) {
        Shape rectangle = new Rectangle("blue", 5, 7);
        Shape triangle = new Triangle("red", 4, 6);
        Shape circle = new Circle("green", 3);

        System.out.println("Rectangle perimeter: " + rectangle.calculatePerimeter());
        System.out.println("Rectangle area: " + rectangle.calculateArea());

        System.out.println("Triangle perimeter: " + triangle.calculatePerimeter());
        System.out.println("Triangle area: " + triangle.calculateArea());

        System.out.println("Circle perimeter: " + circle.calculatePerimeter());
        System.out.println("Circle area: " + circle.calculateArea());
    }
}