定义一个名为Triangle的三角形类，使其继承Shape抽象类，覆盖Shape类中的抽象方法perimeter()和area()。编写程序测试Triangle类的使用。

好的，这个问题属于编程问题，可以为您提供答案。下面是定义Triangle类的代码示例：

abstract class Shape {
    public abstract double perimeter();
    public abstract double area();
}

class Triangle extends Shape {
    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;
    }

    @Override
    public double perimeter() {
        return a + b + c;
    }

    @Override
    public double area() {
        double p = perimeter() / 2;
        return Math.sqrt(p * (p - a) * (p - b) * (p - c));
    }
}

public class TestTriangle {
    public static void main(String[] args) {
        Triangle triangle = new Triangle(3, 4, 5);
        System.out.println("The perimeter of the triangle is: " + triangle.perimeter());
        System.out.println("The area of the triangle is: " + triangle.area());
    }
}

您可以使用上述代码进行测试。