java 判断点是否在一条线段上

```
public static void main(String[] args) {
	Scanner scan = new Scanner(System.in);
	Point point1 = new Point();
	Point point2 = new Point();
	double x, y;
	point1.setLocation(5.0, 5.0);
	point2.setLocation(1.0, 1.0);
	System.out.println("请分别输入点x,y的坐标：");
	x = scan.nextDouble();
	y = scan.nextDouble();
	boolean pdline = (x - point1.getX()) * (point1.getY() - point2.getY()) == (point1.getX() - point2.getX())
			* (y - point1.getY());
	if (pdline) {
		System.out.println("您输入的点在该条直线上");
	} else {
		System.out.println("您输入的点不在该条直线上");
	}

	scan.close();
}
```