都说两点确定一条直线，那么设计一个直线类Line，需要通过两个点Point对象来确定。Line类具体要求如下： 1)定义两个Point对象p1，p2； 2)写出有参构造方法，传递两个对象值给p1，p2 3）为p1，p2写出setters，和getters方法 4）为Line写出一个getLength方法求直线中两点的长度 5) 为LIne写一个ToString方法，方法如下所示： public String toString() { return "Line [p1=" + p1 + ", p2=" + p2 + "]"; } 在Main类的main方法中，定义一个Line数组，数组长度通过键盘给出，然后通过键盘为每线段的两个Point对象的坐标赋值，并生成相应Line对象放入数组中，循环数组，输出每条直线的信息，以及两个点之间的距离。 Point 类如下所示： public class Point { private int x, y;// x,y为点的坐标 //求两点之间的距离 public double distance(Point p1) { return Math.sqrt((p1.x -this.x)*(p1.x -this.x)+(p1.y-this.y)*(p1.y-this.y)); } public Point(int x, int y) { super(); this.x = x; this.y = y; } public int getX() { return x; } public void setX(int x) { this.x = x; } public int getY() { return y; } public void setY(int y) { this.y = y; } public Point() { super(); x = y =0; } @Override public String toString() { return "Point [x=" + x + ", y=" + y + "]"; } }

下面是Line类的代码实现：

public class Line {
    private Point p1, p2;

    public Line(Point p1, Point p2) {
        super();
        this.p1 = p1;
        this.p2 = p2;
    }

    public Point getP1() {
        return p1;
    }

    public void setP1(Point p1) {
        this.p1 = p1;
    }

    public Point getP2() {
        return p2;
    }

    public void setP2(Point p2) {
        this.p2 = p2;
    }

    public double getLength() {
        return p1.distance(p2);
    }

    @Override
    public String toString() {
        return "Line [p1=" + p1 + ", p2=" + p2 + "]";
    }
}

在Main类的main方法中，实现对Line数组的输入和输出：

public static void main(String[] args) {
    Scanner scanner = new Scanner(System.in);
    System.out.print("请输入Line数组的长度：");
    int n = scanner.nextInt();
    Line[] lines = new Line[n];
    for (int i = 0; i < n; i++) {
        System.out.print("请输入第" + (i + 1) + "条直线的p1点的x坐标：");
        int x1 = scanner.nextInt();
        System.out.print("请输入第" + (i + 1) + "条直线的p1点的y坐标：");
        int y1 = scanner.nextInt();
        System.out.print("请输入第" + (i + 1) + "条直线的p2点的x坐标：");
        int x2 = scanner.nextInt();
        System.out.print("请输入第" + (i + 1) + "条直线的p2点的y坐标：");
        int y2 = scanner.nextInt();
        Point p1 = new Point(x1, y1);
        Point p2 = new Point(x2, y2);
        Line line = new Line(p1, p2);
        lines[i] = line;
    }
    for (int i = 0; i < n; i++) {
        System.out.println("第" + (i + 1) + "条直线是：" + lines[i].toString());
        System.out.println("第" + (i + 1) + "条直线的长度是：" + lines[i].getLength());
    }
}