Java 报错求解答 non-static variable this cannot be referenced from a static context

Java 报错求解答 non-static variable this cannot be referenced from a static context

错误1：大括号位置有误
错误2：zui.getVolume()拼错
下面是改正后的完整代码
abstract class GraphicObject {
public abstract double getArea();// 抽象方法
}


class TiXing extends GraphicObject {
double a, b, h;

TiXing(double a, double b, double h) {
this.a = a;
this.b = b;
this.h = h;
}

public double getArea() {
return (a + b) * h / 2;
}
}


class Circle extends GraphicObject {
double r;

Circle(double r) {
this.r = r;
}

public double getArea() {
return 3.14 * r * r;
}
}

class Zhui {
GraphicObject bottom;
Double height;

Zhui(GraphicObject bottom, double height) {
this.bottom = bottom;
this.height = height;
}

void setBottom(GraphicObject bottom) {
this.bottom = bottom;
}

public double getVolum() {
return (bottom.getArea() * height) / 3;
}
}

public class aa {
public static void main(String args[]) {
Zhui zui;
GraphicObject tuxing;
tuxing = new TiXing(2, 3, 4);
System.out.println("梯形的面积是" + tuxing.getArea());
zui = new Zhui(tuxing, 30);
System.out.println("梯形底的锥的体积是" + zui.getVolum());
tuxing = new Circle(10);
System.out.println("圆形的面积是" + tuxing.getArea());
zui.setBottom(tuxing);
System.out.println("圆锥的体积是" + zui.getVolum());
}
}

主函数是静态的，必须调用静态方法。最简单的方法，把get写成静态吧。