用Java生成三角形，圆，矩形的面积和周长

Sure, 我可以回答你的问题。

下面是 Java 生成三角形，圆，矩形的面积和周长的示例代码。

Triangle.java:

public class Triangle {
    private double base;
    private double height;
    private double side1;
    private double side2;
    private double side3;

    public Triangle(double base, double height, double side1, double side2, double side3) {
        this.base = base;
        this.height = height;
        this.side1 = side1;
        this.side2 = side2;
        this.side3 = side3;
    }

    public double getArea() {
        return 0.5 * base * height;
    }

    public double getPerimeter() {
        return side1 + side2 + side3;
    }
}

Circle.java:

public class Circle {
    private double radius;

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

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

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

Rectangle.java:

public class Rectangle {
    private double width;
    private double height;

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

    public double getArea() {
        return width * height;
    }

    public double getPerimeter() {
        return 2 * (width + height);
    }
}

你可以在你的应用程序中创建这些类的实例，然后使用它们的方法来获取它们的面积和周长，如下所示:

Triangle triangle = new Triangle(3, 4, 5, 4, 3);
double triangleArea = triangle.getArea();
double trianglePerimeter = triangle.getPerimeter();

Circle circle = new Circle(2);
double circleArea = circle.getArea();
double circlePerimeter = circle.getPerimeter();

Rectangle rectangle = new Rectangle(6, 9);
double rectangleArea = rectangle.getArea();
double rectanglePerimeter = rectangle.getPerimeter();

Hope that helps!