java设计图形Shape类及其子类圆Circle和矩形Rectangle类。图形Shape类中包括位置坐标(x,y),圆类Circle新增半径r,矩形Rectangle类新增宽w和高h，编写三个类的构造方法实现成员变量初始化。

下面是Java代码实现：

public class Shape {
    private int x;
    private int y;

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

    public int getX() {
        return x;
    }

    public int getY() {
        return y;
    }
}

public class Circle extends Shape {
    private int r;

    public Circle(int x, int y, int r) {
        super(x, y);
        this.r = r;
    }

    public int getR() {
        return r;
    }
}

public class Rectangle extends Shape {
    private int w;
    private int h;

    public Rectangle(int x, int y, int w, int h) {
        super(x, y);
        this.w = w;
        this.h = h;
    }

    public int getW() {
        return w;
    }

    public int getH() {
        return h;
    }
}

其中，Shape是基类，Circle和Rectangle是Shape的子类。在Shape类中定义了位置坐标(x,y)两个成员变量和构造方法，Circle类和Rectangle类分别新增了半径r和宽高w、h两个成员变量，并且在构造方法中调用了父类的构造方法来初始化基类的成员变量。