用java实现编写一个代表三角形的类。其中,三条边为三角形的属性,并封装有求三角形的面积和周长的方法。分别针对三条边为3,4,5和7,8,9的两个三角形进行测试。

Triangle.java

public class Triangle {
    private double a;
    private double b;
    private double c;

    public Triangle(double a, double b, double c) {
        this.a = a;
        this.b = b;
        this.c = c;
    }

    public double getA() {
        return a;
    }

    public double getB() {
        return b;
    }

    public double getC() {
        return c;
    }

    public double getArea() {
        double p = (a + b + c) / 2;
        return Math.sqrt(p * (p - a) * (p - b) * (p - c));
    }

    public double getPerimeter() {
        return a + b + c;
    }
}

Test.java

public class Test {
    public static void main(String[] args) {
        Triangle t1 = new Triangle(3, 4, 5);
        System.out.println("Triangle 1:");
        System.out.println("Sides: " + t1.getA() + ", " + t1.getB() + ", " + t1.getC());
        System.out.println("Area: " + t1.getArea());
        System.out.println("Perimeter: " + t1.getPerimeter());

        Triangle t2 = new Triangle(7, 8, 9);
        System.out.println("Triangle 2:");
        System.out.println("Sides: " + t2.getA() + ", " + t2.getB() + ", " + t2.getC());
        System.out.println("Area: " + t2.getArea());
        System.out.println("Perimeter: " + t2.getPerimeter());
    }
}

输出结果：

Triangle 1:
Sides: 3.0, 4.0, 5.0
Area: 6.0
Perimeter: 12.0
Triangle 2:
Sides: 7.0, 8.0, 9.0
Area: 26.832815729997478
Perimeter: 24.0