先创建一个Point类，然后定义Triangle类。在Triangle类中定义三个Point的对象用来表示一个三角形的三个点，再定义一个方法setTri对这三个点进行初始化，然后定义两个方法求三角形的周长、面积。在main()中创建一个三角形对象，求给定三点的三角形的周长、面积

### 回答1：
下面是代码实现：

import math

class Point:
    def __init__(self, x=0, y=0):
        self.x = x
        self.y = y

class Triangle:
    def __init__(self):
        self.p1 = Point()
        self.p2 = Point()
        self.p3 = Point()

    def setTri(self, x1, y1, x2, y2, x3, y3):
        self.p1.x = x1
        self.p1.y = y1
        self.p2.x = x2
        self.p2.y = y2
        self.p3.x = x3
        self.p3.y = y3

    def getSideLength(self, p1, p2):
        return math.sqrt((p1.x - p2.x) ** 2 + (p1.y - p2.y) ** 2)

    def getPerimeter(self):
        a = self.getSideLength(self.p1, self.p2)
        b = self.getSideLength(self.p2, self.p3)
        c = self.getSideLength(self.p3, self.p1)
        return a + b + c

    def getArea(self):
        a = self.getSideLength(self.p1, self.p2)
        b = self.getSideLength(self.p2, self.p3)
        c = self.getSideLength(self.p3, self.p1)
        s = (a + b + c) / 2
        return math.sqrt(s * (s - a) * (s - b) * (s - c))

# 测试
t = Triangle()
t.setTri(0, 0, 3, 0, 0, 4)
print("周长：", t.getPerimeter())
print("面积：", t.getArea())

输出结果为：

周长： 12.0
面积： 6.0

### 回答2：
首先，我们需要创建一个Point类，这个类用来表示一个点的坐标。使用如下的方法创建Point类：

class Point:
    def __init__(self, x, y):
        self.x = x
        self.y = y

然后，我们需要定义Triangle类，这个类用来表示一个三角形。Triangle类中有三个Point对象，用来表示三角形的三个点。我们使用如下的方法定义Triangle类：

class Triangle:
    def __init__(self):
        self.point1 = Point(0, 0)
        self.point2 = Point(0, 0)
        self.point3 = Point(0, 0)

    def setTri(self, x1, y1, x2, y2, x3, y3):
        self.point1 = Point(x1, y1)
        self.point2 = Point(x2, y2)
        self.point3 = Point(x3, y3)

    def getPerimeter(self):
        # 计算三角形的周长
        side1 = math.sqrt((self.point1.x - self.point2.x) ** 2 + (self.point1.y - self.point2.y) ** 2)
        side2 = math.sqrt((self.point2.x - self.point3.x) ** 2 + (self.point2.y - self.point3.y) ** 2)
        side3 = math.sqrt((self.point3.x - self.point1.x) ** 2 + (self.point3.y - self.point1.y) ** 2)
        perimeter = side1 + side2 + side3
        return perimeter

    def getArea(self):
        # 计算三角形的面积
        side1 = math.sqrt((self.point1.x - self.point2.x) ** 2 + (self.point1.y - self.point2.y) ** 2)
        side2 = math.sqrt((self.point2.x - self.point3.x) ** 2 + (self.point2.y - self.point3.y) ** 2)
        side3 = math.sqrt((self.point3.x - self.point1.x) ** 2 + (self.point3.y - self.point1.y) ** 2)
        s = (side1 + side2 + side3) / 2
        area = math.sqrt(s * (s - side1) * (s - side2) * (s - side3))
        return area

最后，在main()函数中，我们可以创建一个Triangle对象，然后调用setTri方法对三个点坐标进行初始化，并调用getPerimeter和getArea方法分别求解三角形的周长和面积，如下所示：

import math

def main():
    triangle = Triangle()
    triangle.setTri(0, 0, 3, 0, 0, 4)
    perimeter = triangle.getPerimeter()
    area = triangle.getArea()
    print("三角形的周长为：", perimeter)
    print("三角形的面积为：", area)

if __name__ == "__main__":
    main()

这样，我们就可以获得给定三个点的三角形的周长和面积了。

### 回答3：
Point类定义如下：

public class Point {
    private double x;
    private double y;
  
    public Point(double x, double y) {
        this.x = x;
        this.y = y;
    }
  
    public double getX() {
        return x;
    }
  
    public double getY() {
        return y;
    }
}

Triangle类定义如下：

public class Triangle {
    private Point point1;
    private Point point2;
    private Point point3;
  
    public void setTri(Point p1, Point p2, Point p3) {
        point1 = p1;
        point2 = p2;
        point3 = p3;
    }
  
    public double getPerimeter() {
        double side1 = calculateDistance(point1, point2);
        double side2 = calculateDistance(point2, point3);
        double side3 = calculateDistance(point3, point1);
        return side1 + side2 + side3;
    }
  
    public double getArea() {
        double side1 = calculateDistance(point1, point2);
        double side2 = calculateDistance(point2, point3);
        double side3 = calculateDistance(point3, point1);
        double s = (side1 + side2 + side3) / 2;
        return Math.sqrt(s * (s - side1) * (s - side2) * (s - side3));
    }
  
    private double calculateDistance(Point p1, Point p2) {
        double xDiff = p2.getX() - p1.getX();
        double yDiff = p2.getY() - p1.getY();
        return Math.sqrt(Math.pow(xDiff, 2) + Math.pow(yDiff, 2));
    }
}

在main()函数中，创建一个三角形对象并计算周长和面积：

public static void main(String[] args) {
    Point p1 = new Point(0, 0);
    Point p2 = new Point(0, 5);
    Point p3 = new Point(3, 0);
    
    Triangle triangle = new Triangle();
    triangle.setTri(p1, p2, p3);
    
    double perimeter = triangle.getPerimeter();
    double area = triangle.getArea();
    
    System.out.println("三角形的周长为：" + perimeter);
    System.out.println("三角形的面积为：" + area);
}

以上代码创建了一个三角形对象，给定了三个点的坐标，并计算出了三角形的周长和面积。