public Rect(int width,int height){this(0,0,width,height);}

Question

this只的就是当前编译的类this(0,0,width,height);给Rect的域变量(x1,y1,x2,y2)赋值

Answer 1

public class Rect
{
public int x1,y1,x2,y2;
public Rect(int width,int height)
{
this(0,0,width,height);
}
public Rect(int a,int b,int c,int d)
{
x1 = a;
y1 = b;
x2 = c;
y2 = d;
}
public static void main(String[] args)
{
Rect a = new Rect(1,2);
System.out.println(a.x1);
System.out.println(a.y1);
System.out.println(a.x1);
System.out.println(a.y1);
}
}你看看上面这段代码，我想你应该清楚了