clone

 

 

package one.test;

public class Test {

    static void myMethod(Point pt1) {
        pt1.x = 23;
        System.out.println("x=" + pt1.x);
    }

    public static void main(String[] args) {
        Point pt = new Point(2, 4);
        System.out.println("x=" + pt.x);
        Point pt2 = (Point) pt.clone();
        System.out.println("x=" + pt2.x + " y=" + pt2.y);
        
        myMethod(pt2);
        System.out.println("x=" + pt.x);
    }

}

class Point implements Cloneable {
    int x, y;

    Point(int x, int y) {
        this.x = x;
        this.y = y;
    }

    @Override
    public Object clone() {
       
        Point p = null;
        try {

             //这里并没有对xy赋值，但是却把值拷贝过去了，难道是继承Cloneable的结果？

            p = (Point) super.clone(); 
        } catch (Exception e) {
            e.printStackTrace();
        }
        return p;
    }
}

x=2
111111
x=2 y=4
x=23
x=2